The Infected are everywhere, and have one goal in mind; kill the survivors. This page lists all of the types of Infected you will come across, how to deal with them as a survivor, and how to play them in Versus mode. Health values where given are based on the Versus values, but in single player/campaign modes health values of special infected vary somewhat depending on how you are doing and the difficulty you are playing on.
- Health: Variable (usually less than 50)
- Abilities: None (besides clawing and kicking)
The Horde are by far the most common enemy, and are little more than zombified versions of ordinary people. However, they are most certainly not slow - they can outrun the survivors. Although they are weak individually, they often make up for it in sheer number. Fortunately, their head is very weak, and one shot from any weapon to the head will kill them. These zombies are generally the first responders to any alarm, whether from a car, building, or from any other source of loud noise.
When they arrive in groups of 20 infected or more, you will have to defend yourself quickly. If they charge in a single file line, they're easily eliminated with rapid fire weapons, but can also be torched as they run through a flaming area. When they manage to get close, you may need to bash them away, throw a pipe bomb or boomer bile to distract them, or swing a melee weapon at them.
Players cannot play as members of the Horde, although when playing as one of the lesser special infected (i.e. not the Tank) it is often advantageous to time your attacks with Horde swarms to maximize the chaos you can cause.
In each of the five campaigns, you will occasionally encounter a infected that behaves different than normal.
- In Dead Center, Zombies are wearing CEDA biohazard suits, making them fireproof. They also have a chance of dropping Bile Bombs. Rarely, an infected Jimmy Gibbs Jr spawns during the finale. He has a lot of health, is immune to fire like the CEDA infected, can blind you with oil like the mudmen and ignores bile bombs and pipe bombs.
- In The Passing, there will be infected survivors with high health, but they run as soon as they're shot, and they drop pipe bombs, molotovs, first aid kits and pills. He's very hard to headshot due to his bulletproof helmet and he's immune to fire ammunition.
- In Dark Carnival, Clown zombies will squeak as they move, attracting the horde. You can also honk their horn with a melee shove, letting you get an achievement.
- In Swamp Fever, Mudmen will crawl towards you at a much faster speed than normal infected, and their attacks will try to blind you with mud.
- In Hard Rain, there are construction workers wearing hard hats and mufflers; they will ignore pipe bombs. They're also more resistant to melee shoves.
- In The Parish, some zombies are wearing full frontal body armor; bullets will bounce off harmlessly while melee attacks can't put a scratch on them. The trick to killing one is to hit them from behind. They sometimes drop Nightsticks.
- Health: 50
- Abilities: Vomiting, exploding
Boomers don't look menacing; they're morbidly obese, and slow. Unfortunately they are also full of Horde-attracting vomit. If these get too close they can puke all over you, severely reducing your vision and attracting a swarm of the Horde to attack you. Moreover, when they die, they explode, showering everything in the nearby area with the stuff, and that includes any survivors that are too close. The vomit effect lasts for about 20-25 seconds. During this time, be advised that it becomes very difficult to see, and the telltale halos and names of other survivors disappear, as well as having the vomit music playing over the top. As a result, you cannot distinguish a pounced or constricted survivor except by reduced vision, and survivors may look a lot like infected.
To minimize the damage that a Boomer can cause, kill it from a distance so it can't shower anyone nearby with its bile, and so it can't vomit over anyone. If you find yourself toe-to-toe with a Boomer, quickly hit it with your melee attack, which will stun it and knock it back. Put a little more distance between you, then shoot it. In this regard Boomers are very easy to kill, but this is a drawback when you shoot one that is suddenly face to face with you by accident. DO NOT attack them using a melee weapon, as you're guaranteed to get bile on you after killing it.
When playing as the Boomer, your goal is chaos; you lack the ability to deal damage directly. Make sure that the survivors don't have chance to kill you before you can get within exploding range/vomit range; hide behind corners or on top of objects that the survivors can't see the top of. Your survivor-vision will allow you to see the survivors as they approach, so wait until they're about to spot you and start vomiting. You'll most likely get one of them, and if your enemy is suitably surprised you might be able to get closer and be shot, showering more of them with bile. However, try not to be immediately obvious as to where you are hiding, as survivors can often hear your telltale throwing up sounds from a short distance. Alternatively, if you want to deny your foes a chance to safely dispose of you, drop onto them from a tall ledge; if you fall far enough you will automatically die upon hitting the ground, exploding like a bomb over the survivors.
Also, it is worthwhile to note when playing as the Smoker and Hunter that the Boomer's vision/halo obstruction means that many teams will not be able to detect a helpless survivor until their vision has returned or the music has stopped playing after survivors have been recently-Boomered. Therefore, it's generally a good idea to attack non-Boomered survivors since their friends may not notice in time.
The most challenging aspect of playing a Boomer is getting into range of Survivors, particularly in outdoor areas. Often attacking from the top of a climb point is the best option in this situation, as you can just throw yourself into Survivors who will goo themselves when they attack you. If they clue onto this and start shoving and finding range, run right after them, claw them in the back, then back up quickly. They should miss the next shove, at which stage you run in and they'll be frustrated enough to shoot. Ideally this leaves them at the back, and the only one covered in bile.
- Health: 250
- Abilities: Constricting, releasing gas clouds
The Smoker is tall and lanky, but the main thing is his ridiculously long tongue. This can easily reach distances of 100 feet when stretched, and if it connects with a survivor will wrap around them and begin to drag them back towards him. After a few seconds of being wrapped the survivor can no longer move, and if they are pulled against a solid object, suspended from above, or dragged into the Smoker's waiting grasp, they will start to take damage. A survivor that has been in the grip of the Smoker's tongue for too long can no longer rescue themselves, and must be saved. Upon death, the Smoker also releases a cloud of thick smoke, which obscures vision and also causes any survivor who walks through it to start coughing for a few seconds, preventing voice communication.
You can save a fellow survivor in four ways; melee the Smoker, kill it, melee the trapped survivor, or shoot the tongue. You will hear the telltale music spike when a survivor has been constricted, so quickly find them and free them before they start taking damage either from being constricted or from attacking members of the Horde. Being completely constricted deals anywhere between 5 and 30 damage per second or two depending on the difficulty you're playing on, so make sure you spot entangled survivors quickly. Smokers will often try and attack from obscured positions like rooftops, through windows, or from just around a corner, and try to stick close to a straggling survivor in case a Smoker decides to attack them and the survivor cannot use the brief period of control that they have to kill the Smoker. You can also see where one has been recently killed by the spore trail it leaves behind in the air as it walks.
When playing as the Smoker, your ideal role is to break up the survivor formation. Dragging a survivor away from the group opens them up to attack from the Horde or other specials, and this effect is only amplified if you can drag one off of an object or into an awkward position which opens up any rescuer to attack also. Attacking from obscured positions as previously mentioned will increase the chance that your tongue will grab and pull a survivor, as well as making it more difficult for survivors to opt for the better method of saving their friend; by killing you. Landing yourself in survivors and hacking away at them with your secondary claw attack is also a good strategy to try, especially during a particularly severe Horde swarm in a cramped place, as on top of the swarms when you die you will obscure the survivor's vision, making it a lot more difficult for them to fight back.
If there are any cars with alarms or witches around, a great strategy would be to stand behind it and pull someone towards it with your tongue. When the teammates shoot at you, they may hit the witch or alarm causing even more havoc. Alternatively, try aiming for spots which drag survivors off ledges; although they don't lose much actual health from this if they are helped up it still incapacitates a survivor.
An effective strategy around handrails and trees is to shoot the tongue from cover. Survivors will usually push your victim free, but everyone but the pusher will assume you are dead. This gives you a brilliant opportunity to quickly find a different angle, or snag that same guy back again. Any injured survivors will tend towards the back of the formation because of their reduced movement speed, so even when you see a tight formation, lining up the "limper" will usually present an opportunity to drag them backwards.
- Health: 250
- Abilities: Leaping, pinning survivors
The only real distinguishing features of the Hunter compared to other infected are the fact that they crawl a lot more, leap around, and have a hood. The Hunter's main attack is its pounce, which after crouching for a short amount of time will allow them to leap a great distance. If this leap hits a survivor, they will be instantly pinned, unable to fight back as the Hunter rips their torso to shreds. Also, there can be more than one Hunter in action at any given time, unlike with all other special infected.
As with the Smoker's constricting tongue, the Hunter's pounce leaves a survivor helpless, so it's important to save any survivor you see pinned as quickly as possible; being pinned can take off a lot of health in a short amount of time (between 5 and 25 health per second or so depending on the difficulty). Unlike with the Smoker, however, a survivor is rendered helpless immediately, and will start taking damage from only a second or two after the Hunter has pounced them (in some cases the pounce itself will knock off health). Hunters are also very agile, and should one live through an attack on you, it can very quickly retreat and leap out of sight. Either kill or melee a Hunter pinning a survivor to free them. Stragglers are also a prime target for Hunters, so make sure you do not go too far ahead of a slow-moving team member in case they get pounced.
When playing as a Hunter, you should aim to cause havoc and assist fellow infected where possible. A Hunter pouncing into a close formation of survivors will likely do no damage even if the pounce connects, as you will just get melee'd off or killed before you can start dealing damage. Instead, try and target survivors that are a bit ahead or behind, to maximise the chance that you will survive long enough to deal damage. The exception to this is pouncing from great height, which can deal up to 25 dmg. This can be exceptionally handy if you need to take the "edge" off a particular player who's staying centered and defending his team, or to quickly kill off survivors crossing an open area. During the pounced animation, the hunter is crouched low enough that benches, desks and the bottoms of stairwells can provide adequate cover, even if other survivors are near, just deny them the angle for a response shot. Even better, make your presence known to a lone wolf, make him run for cover, then pounce him once he's holed up out of range of saving. The Hunter is fast enough to effectively harass and intimidate the other team without pulling the trigger right away. You are most likely to deal a significant amount of damage however by pouncing a survivor in one of the following situations:
- Caught in a Horde swarm (the surrounding Horde act as a temporary meat shield from survivor fire).
- Saving someone constricted or pounced (by another Hunter).
- More than a ten-second time gap away from another survivor.
- Top or bottom of a ladder or stairwell where angles are convoluted and survivors have to move in single file.
- Single survivor holing up in a room or ducking behind cover.
- When Survivors break into pairs and another Infected makes a move, pounce the victim's buddy and force the whole team backwards while inflicting damage.
- When a Survivor is "psyched out" you can chase him away from his team and then pounce him.
In Versus 10 seconds equates to roughly 30-50 damage, and if everything goes well it might be longer before you are removed from the survivor you are ravaging. Also, longer pounces, in which the Hunter spends longer in the air, will do contact damage upon connecting with a survivor, up to a maximum of 25 damage. Pounces which exceed 15 damage are generally difficult to pull off but if successful is a significant contributor to the infected team, and will put low-health survivors even closer to the critical incap point.
- Health: 100
- Abilities: Corrosive spit, exploding
The Spitter is a new special infected to L4D2, and one of the more unsettling in terms of appearance. She is quite tall, with a disturbingly long neck and a bloodied, half-dissolved bottom jaw. She also dribbles bright green goo as she walks around. She can spit a corrosive spitball a significant distance, which will drop to the ground and explode, making a puddle of bright green acid which will inflict continuous damage on any survivor standing in it. This damage rate increases the longer the survivor stands in it and will dissipate after 8 seconds or so. When killed, the Spitter will explode, dropping the same corrosive substance in a much smaller puddle.
Good awareness is critical to dealing with the Spitter safely. She does not need to be close to unleash her special ability, as she is able to attack from the greatest distance of any Infected excluding the Tank's rocks, and in addition her signature noises are not as prominent as that of the other lesser SI, especially the Jockey, Boomer and Hunter. Spotting her and eliminating her before she has time to spit will invariably save your team some hassle. A puddle of spit on survivors in a cramped room is virtually guaranteed to shear off at least 50 points of health across the entire team, if not more. In open areas, although you may still take a tiny bit of damage from initially standing in the spit puddle, it is much easier to escape from and dodge. As a result, if you have to go through cramped rooms, try and coax Spitters into attacking and being killed before you enter.
In Scavenge mode, or any finale (namely Dead Center's) involving gas can collection, note that the Spitter's spit can ignite dropped cans. AI Spitters won't deliberately spit on cans, but human players definitely will. Leaving large amounts of cans unattended is asking for trouble. A can will survive for about 4 seconds in spit before it ignites, and the fire from it will ignite any nearby cans. It is adviseable, if you go for the 2 and 2 split during games in which this configuration is appropriate, that the collector pair throws cans down separated from one another so as spitter spit cannot get multiple cans either from the spit or indirectly from resulting flames.
Timing is critical to dealing damage as any special infected, but correctly timed Spitter attacks are lethal to the survivors. The spit puddle is a useful attack in a whole variety of different situations, which means it's very easy to deal at least some damage as her. There are a number of situations in which a spitter attack can really put the heat on:
- Survivors surrounded by the horde. As they are under attack, they will find it very difficult to move, and will be exposed to your spit for longer.
- Survivors in cramped places. As they cannot run in any direction they choose to escape the spit, they will often have to spend longer standing in it before they can get out. This scenario also increases the chance that the survivors are cramped together and your spit will affect all of them.
- Survivors under attack from other specials. Your spit will add damage on top of the damage they are sustaining from being ridden/pummelled/constricted/pounced, and furthermore the survivor cannot escape it. This is highly likely to incapacitate the unfortunate survivor caught in it, and will also prevent immediate revival if they do go down and the other SI is eliminated; as the spit will persist and survivors will not (generally) be stupid enough to try and pull them up whilst standing in spit.
- Survivors moving to rescue an incapacitated/pinned teammate. The spit also works as area denial, so if a survivor is in trouble you can force the remaining team members to sustain damage if they wish to rescue immediately.
- Over a generator in Scavenge. This delay can often be enough for a well-coordinated infected team to begin an attack which further prevents any gas gathering. If the survivor team is pushed for time, they may attempt to pour through your spit, which will do huge amounts of damage to them and may cause them to fail by becoming incapped, dropping the can into the spit, and then it setting on fire.
- Near any large number of cans gathered together. Survivors will often immediately try and get the cans out of the spit, which causes them to take damage. If the number of cans is a lot, survivors may spend longer in the spit, or will fail to get them all and cause one or more to ignite. They may even attempt to rescue the cans in priority over a pinned teammate, further increasing the damage your infected teammate does.
In total these opportunities show up a lot as Spitter, making her very useful and very dangerous. However, with 100 health she is very weak indeed, and like with the Smoker, as you can attack from range, do so, and from obscured positions wherever possible. Especially in Scavenge, any survivor team worth their salt will be on the lookout for you to stop you causing havoc. The Spitter is not particularly slow, so if you are threatened, move to cover immediately. Attack from a different angle next time to avoid a survivor waiting for you to return to your previous position and killing you.
- Health: 325
- Abilities: Leaping, riding survivors
The Jockey is another new special to L4D2, and it looks like a midget-sized infected with a bit of a hunched back and an oddly-elongated body and arms. It will attempt to leap onto other players and ride them whilst slowly clawing at their back, whilst trying to pull the survivor away from the group and into other hazards. The Jockey possesses a distinct maniacal laugh and a partly-hopping gait, both of which are easy to identify.
Being ridden is a pin, so the victim cannot save themselves. However, whereas being attacked by any other special infected in this manner leaves you totally powerless to fight back, you can resist the Jockey to a limited extent, slowing the rate at which it pulls you away from your teammates or towards danger. Shooting the Jockey is somewhat difficult; it's fast and small, and furthermore will locate itself on the back of the survivor they ride, opening up the survivor themselves to any friendly fire damage incurred whilst trying to remove it. At 325 health it's also marginally tougher than a Hunter or Smoker - in this way it is amongst one of the most powerful normal special infected, possessing toughness, maneuverability (its leap is actually very good for crossing obstacles or attacking from blind spots) and a pinning attack. Fortunately, however, a Jockey's pinning attack does very little damage over time, instead relying on the ensuing chaos and environmental/enemy hazards to deal damage. A ridden survivor spotted early can be saved quickly without sustaining much damage at all. As with the Hunter or Smoker, you can also melee the pinned survivor to knock the Jockey off. Note that a Jockey cannot continue to pin the survivor they've ridden if the survivor becomes incapacitated; the Jockey will fall off and the survivor will draw their pistol(s) as normal.
The Jockey can cause utter chaos if its attack is timed correctly. Distracted survivors may not notice a Jockey sneak up and whisk one of them away, and before they know it the survivor has been pulled a fair distance, opening up the rescuer and the ridden survivor to attack from other more-directly dangerous special infected or the horde. As the Jockey is so easy to spot and deal with quickly for an aware group, and unlike the Boomer possesses no penalty for dealing with him at an inappropriate time, you must rely on attacking from blind spots or during distractions to actually cause any real damage. However, done correctly, this will cause the situation to spiral out of control, and may very quickly cause the team's demise. An incap is usually possible with help from the environment or other infected in very little time, and you are able to choose to a certain extent where they are incapacitated. If a Boomer manages to get more than 2 survivors covered, you can cause mayhem with impunity; the survivors will not realise or be able to help, usually, until far too late. However, remember that your pin only lasts until they are incapacitated, and afterwards your normally-instant cooldown for leaping will extend to a good 20-30 seconds.
There are a number of hazards that are good to drag a survivor into:
- Over any edge. If the survivor is critical (black-and-white vision) they will die instantly, if they aren't, they will hang, but are unable to even fire pistols. Note that this will kill you if the drop leads out of the map.
- Into flames. The flames will do continuous damage to you, but will hurt the survivor faster.
- Into spit. This is better than fire, as it will do damage at a faster rate, and will not hurt you in the process.
- Into an oncoming horde. If the horde doesn't go for the ridden survivor, they will act as an obstacle to any rescuers, and if they do, then you are almost guaranteed an incap.
- Through doorways that lead into side-stream hallways and rooms with obstacles. Even a right angled wall can break a team up. This will protect you from long-range fire and make other Survivors risk themselves and lose direction from chasing you into far corners.
- Away from other survivors. This, in itself, is a hazard.
- Health: 600
- Abilities: Charging, Pummelling
The Charger is a smaller version of the Tank in some ways, recognisable by its one strong arm, with the other, withered arm hanging oddly off the other side. Its main form of attack is to bullrush at full speed, either knocking survivors over or carrying one with it. Upon running far enough, or being stopped by an obstacle, it will start to pummel the poor survivor it picked up into the ground, sometimes even battering a nearby wall with them, or flinging them against a ceiling. The Charger has a (somewhat quiet) distinctive gurgling yell of sorts, and its size and appearance make it easy to spot, but its sheer speed can allow it to make surprise attacks.
With 600 health the Charger is very tough, and during a rush is almost impervious to damage from the front. He is also totally immune to melee attacks; you cannot stun him with one, nor can you free a survivor he is pummelling with one. The pummelling also inflicts a lot of damage very quickly (although this is reduced to a trickle on incapacitated survivors). A Charger will also inflict contact damage during a rush, as well as upon the survivor it carries if it runs into a wall or solid object. It may even carry a survivor over edges, either inflicting a ton of fall damage or an instant kill (which most of the time also kills the Charger in the process). Furthermore, it also has the most powerful melee attack of any normal special infected.
Fighting a Charger in open space almost renders it harmless; its charge is fairly easy to dodge given room, although it does move fairly fast even when not rushing and may be able to reach a survivor to punch them before it dies. During a rush it is still vulnerable to attacks from the side or rear, and it's possible to kill a Charger in mid-charge by shooting it in the back enough. Providing it doesn't suicide, the Charger will usually manage to inflict some damage on someone, but in most circumstances it is little more than an annoyance...if it's controlled by the AI.
Controlled by players, the Charger is actually capable of instantly killing an entire team of four in a single charge if it attacks at the correct time. The fact that it can also cause a kill arguably even more easily than the Tank makes it VERY dangerous in the hands of a competent player, and furthermore, to be effective, it doesn't need to attack with other special infected. However, as previously mentioned, the Charger becomes much, much easier to deal with in open space; so avoid attacking then. Any place with an edge nearby, or any long straight path is a perfect place to attack. Here are examples:
- The outside ledges of the hotel in Dead Center 1. Easily the single most effective place in the normal maps to attack. It is possible to kill the entire team instantly by knocking or carrying people off if they are all standing on it.
- The long, straight overpass in Dead Center 2. You are likely to hit everyone here.
- Any escalator in Dead Center 3, or from behind the corner of the door leading to the alarm shut-off room during the crescendo.
- With luck you can knock people over the handrails on the higher levels of the atrium in Dead Center 4 for an instant kill from fall damage.
- The motel upstairs level in Dark Carnival 1. Easy to hit lots of people and carry them a fair distance here.
- Parts of the tunnel of love in Dark Carnival 3, or especially on the straight sections of the rollercoaster track. With luck, you can knock people off the track, dealing a lot of fall damage and setting them further back.
- The crescendo alley in Dark Carnival 4. The horde will add to the chaos you will cause, or will give a new horde time to spawn if it has been dealt with.
- The riverbank in Swamp Fever 1's crescendo. This is an instant kill for anyone carried into the deep water.
- Anywhere around the aircraft in Swamp Fever 2's crescendo. You'll either hit a lot of people or carry one of them off into a lot of danger from the horde.
- Around the raised shacks in Swamp Fever 3, near the crescendo. You can cause havoc by knocking people out of the houses during a horde, and it's easy to hit multiple people.
- Off the raised levels of the plantation house, or on the straight centre-section of the garden in Swamp Fever 4.
- The roof of the sugar mill near the elevator in Hard Rain 2 (and 4, but there's no guaranteed horde that time). Over the edge will instantly kill a survivor from fall damage. Off the opposite side, or into the gap in the centre, will also cause an incap (most likely).
- Potentially into the deep water by the boat escape in Hard Rain 5 (this also applies to Swamp Fever 4) for an instant kill. This is hard to time, though.
- On any raised balcony in The Parish. You will cause some fall damage and it is easy to hit multiple people.
- In any long straight section of the CEDA alarm outpost in The Parish 2.
- Crossing the bus blockade near the start of The Parish 3 (for annoyance) or ANYWHERE in the car impound lot (this will cause chaos).
- Off the house roof during the crescendo of The Parish 4.
- Pretty much anywhere on the bridge in The Parish 5. You will either kill someone by carrying or knocking them off an edge or into a hole, carry them a significant distance, or hit them all as they're standing in a line. Or all three.
With timing and a bit of luck, you will do a lot of damage at any of these points. With enough time, during a distraction for example, a Charger can quite easily incapacitate a survivor after carrying them a distance, so the only times to avoid attacking as a Charger are when they are in an open space and you are not backed up by two or three teammates to provide distractions.
- Health: 3000-8000(depending on difficulty and game mode)
- Abilities: Smacking things, throwing rocks
No need to search for telltale signs of this big, bad, pulsating wall of muscle; every step it takes makes a thud that can be heard for miles and shakes the screen. This is the strongest of all the playable infected (second only to the Witch, who cannot be played as) and the toughest of any enemy you will come across. Up close, its punches do a ton of damage (between 30 and 80, depending on difficulty) and knocks survivors flying, stunning them momentarily. At a distance, it can also throw chunks of rocks ripped from the ground, which do a similar amount of damage and also stun. The Tank can also utilise objects in the environment (like cars) by smacking them into survivors.
The Tank is arguably a boss battle every time it shows up; it takes a significant amount of pounding to go down even with all four survivors shooting it, and it is not particularly slow either. It can cut corners and close in on you, and once you are in range of its fists it can be very difficult to get out of, especially considering that you might lose enough health to start limping, and then there is really no hope. Fighting a Tank in an open environment with few objects for it to use is the best scenario, as you can split up and leave plenty of space to continue running without worrying about it being able to hit you from a distance (you will be able to dodge any rocks it throws). However, in a cramped space or, even worse, a dead end, a Tank (especially on higher difficulties) can spell certain doom for a survivor team. Setting the Tank on fire with a molotov will not damage it, but instead will kill it after a certain amount of time passes (varying from 30 to 40 seconds) so doing so and then dodging it for the remainder of the time is a viable tactic if you have enough room and you are low on ammo.
The Tank's objective is very simple; smash the survivors to pieces. Although this sounds simple, it is a good idea to briefly consider where you are fighting before rushing in with the Tank and engaging the survivors; remember that in open areas the survivors have the upper hand and can quickly whittle down your health. Also, do not change who you attack until your target is incapacitated; this indecision wastes valuable killing time, which to be effective you cannot afford to do. You are more likely to deal a crippling amount of damage by hitting one survivor until they are incapacitated than by trying to hit all of them. However, if you cannot chase down a survivor, hit them with a rock to stun them, or find a closer one to go after. Finally, do not underestimate punchable objects; they are capable of incapacitating any survivor they hit whilst moving.
- Abilities: Powerful claws, one-hit knockdown
The Witch is a passive special infected, known for its distinguished loud weeping. While she may sometimes sit still on the ground, she is also known to walk around the local area during the daytime.
She doesn't want to be disturbed, but if you shine your flashlight at her for too long, shoot her, or stay too close to her, you will anger her, and that's not something you want to do. On all difficulties, one hit from the Witch will incapacitate you, and given how fast she runs, fleeing rarely works. On Expert, this one hit will actually kill you outright even from full health, and to top it off the Witch is easier to startle. Once you are incapacitated, the Witch will scream for a few moments and proceed to continue slashing.
Fortunately, the Witch is only interested in killing the survivor who startled her, and once she has succeeded she will simply run away screaming and covering her face. Also, she does not often have that much health, and a few seconds of sustained fire will often do a decent amount of damage to her, if not kill her. More often than not, though, it is better to avoid the Witch wherever possible. Sometimes however this is not possible, as the Witch may spawn in a doorway or corridor which is impossible to get past without startling her. If this is the case, have everyone take aim at her, then one person fires to startle her, who then runs away. On easier difficulties this usually works especially if the startler gets a bit closer with either shotgun. More experienced players will usually employ a tactic called cr0wning, which involves a shotgun user to fire at the back of the Witch's head. If all the pellets connect, one can easily take down a Witch in one hit.
Even though the witch is powerful and deadly, she can still be confused or blocked by terrain (for example, she can get stuck descending a ladder or climbing a ledge if there is a player in the way.)
You cannot play as the Witch, but when she is around it can sometimes be worthwhile to try and force the survivors to trigger her. Dragging a survivor across a Witch with the Smoker's tongue is always a good bet, or trying to time attacking the survivors as a Boomer so that a Horde swarm appears and one of the survivors accidentally shoots the Witch.