Terraria/Bosses

King Slime
This boss has a rare chance of spawning in the outer forests of the world. A Water Candle from the Dungeon increases the chance of this boss spawning. It can also spawn after many slimes are killed in a Slime Rain, or be summoned by a Slime Crown, requiring 20 Gel and a Gold/Platinum Crown which is made of a Ruby and 5 gold/platinum bars.

It attacks by jumping at you in an attempt to hit you with its large body. It shrinks and spawns Blue Slimes when damaged. In Expert, it also spawns Spiked Slimes.

Eye of Cthulhu
This is the first boss in the game. It is a single floating eye.

The enemy will release miniature eyes, called "Servants of Cthulhu". The eye will spawn around six of them before attempting three charges at the player. These servants are easily handled by shooting at the main iris to take them out as soon as they spawn, but if one slips through, switch to the broadsword.

When it is at half-health, the eye will spin and shed its iris to reveal teeth. It sheds its defense and stops spawning Servants of Cthulhu, but makes stronger charging attacks at the player. In Expert mode, it uses fast, chained together charge attacks.

It appears randomly at night, when at least one player has 200 Health and 4 town NPCs, and is announced by the message "You feel an evil presence watching you...", or may be summoned manually with the Suspicious Looking Eye (crafted from 6 Lenses). It will retreat once daylight approaches.

Eater of Worlds
This boss is only found in the Corruption, its Crimson counterpart is the Brain of Cthulhu.

It is summoned by destroying three shadow orbs, or by summoning it with Worm Food. To create worm food, you need 30 units of Vile powder (created from vile mushrooms or purchased from the Dryad during Blood Moon), and 15 Rotten Chunks (obtained by killing Corruption monsters).

It is a long worm creature that splits when its body segments are killed. In Expert, it will spew Vile Spit from its segments.

Brain of Cthulhu
It is summoned by destroying three crimson hearts, or by summoning it with a Bloody Spine. To create a Bloody Spine, you need 30 units of Vicious powder (created from vicious mushrooms or purchased from the Dryad during Blood Moon), and 15 Vertebrae (obtained by killing Crimson monsters).

It spawns with many Creepers that make it invincible. They fly around it as it teleports. When every Creeper is destroyed, the Brain will teleport around you and charge you. In Expert, it spawns three illusions around you.

It is the only boss vulnerable to knockback.

Queen Bee
The Queen Bee can be spawned by smashing one of her Larvae in an underground Beehive, or using an Abeemination crafted with 5 Honey Blocks, a Stinger, 5 Hive and a Bottled Honey in the Jungle.

She will follow a strict pattern, starting with three times, then hovering above the player and alternating between spawning Bees and rapid-firing Stingers.

Oddly, the Queen Bee can take damage from other enemies or bosses that are not bees or other Queen Bees.

Skeletron
Skeletron is the guardian of the dungeon, and may be summoned only at night by speaking with the old man and selecting "Curse", or killing the Clothier.

When dawn approaches, it receives a massive attack and defense boost, which will kill almost any player.

It spawns with two hands. Its hands will try to slap you, and its head will spin at you. In Expert, it gains a big defense boost when its hands are alive, and it spits out skull projectiles when they are destroyed.

Wall of Flesh
In the underworld, you may encounter a Voodoo Demon, that will drop a Guide voodoo doll. When this doll hits the lava, the Wall of Flesh is spawned.

It consists of two eyes and a mouth that share a health bar. The eyes fire lasers, the fire rate increasing as the boss takes damage. The mouth has defense, and spits out small worms called "Leeches". At the start of the fight, it has several small mouths chained to its body called "The Hungry", which respawn in Expert.

Defeating this boss will thrust your world into Hardmode, creating a new Biome, The Hallow, as well as new monsters that will cause new problems.

The Twins
These two eyes randomly spawn at a 1/30 chance, which increases to 1/20, then 1/10 as the other Mechanical Bosses are defeated, or they can be summoned at night using the Mechanical Eye. Constructing one requires 5 Iron Bars, 3 Lenses, and 6 Souls of Light.

The red one is Retinazer, it fires red Death Lasers and charges. In its second phase, it stops charging and rapidly fires lasers, with the fire rate increasing to near constant as it nears death. The green one is Spazmatism, it fires Cursed Fireballs, charges, and flies in front of Retinazer to shield it. In its second form, it will act similarly to the Eye of Cthulhu's second form, using chain dashes even in Normal. It can also spew a flamethrower of Eye Fire. Both eyes must be defeated for the boss loot.

Queen Slime
The Queen Slime can only spawn by being summoned with a Gelatin Crystal found in the hallowed caves. She will hop around, shooting Regal Gel projectiles in all directions except down, or jump up and slam the ground, creating a shockwave. When hit, she spawns Crystal, Bouncy, and Heavenly Slimes. These will gang up on you in droves. At half health, the Queen will sprout wings and fly around. She now fires Regal Gel down, and flies back up if she drops into a pit with her Queenly Smash.

The Destroyer
This is an upgraded version of the Eater of Worlds. It randomly spawns at night at a 1/30 chance, which increases to 1/20, then 1/10 as the other Mechanical Bosses are defeated, or summoned with a Mechanical Worm, which is constructed using 6 Souls of Night, 6 Rotten Chunks or Vertebrae, and 5 Iron Bars.

Instead of splitting, all segments share HP. They fire lasers until damaged enough to release a laser-firing metal sphere called a "Probe".

Skeletron Prime
This is an upgraded version of Skeletron, randomly spawning at night at a 1/30 chance, which increases to 1/20, then 1/10 as the other Mechanical Bosses are defeated, or is summoned using the Mechanical Skull. You will need 5 Iron Bars, 3 Souls of Light, 3 Souls of Night and 30 Bones.

It consists of a head, a Prime Saw arm, a Prime Cannon arm, a Prime Laser arm, and a Prime Vice arm. The Head will spin at you, the Vice will swing around wildly, the Saw follows a zigzag pattern, the Cannon fires gravity affected Bombs, and the Laser will shoot Death Lasers at you.

When dawn arrives, Skeletron Prime will have increased attack and defense, and will kill the player in a single hit.

Plantera
Plantera has no spawn item, and must be spawned within the Underground Jungle by breaking one of her Bulbs. These bulbs randomly spawn around the Jungle caves after the Wall of Flesh, Twins, Destroyer and Skeletron Prime go down.

She chases you with her three Hooks while firing Seeds, Toxic Seeds and bouncy, gravity-affected Thorn Balls. After she takes enough damage, most of her petals fall away. She creates eight Tentacles attached to herself, with three more attached to each Hook in Expert. Plantera speeds up and does more contact damage, as well as firing Spores instead of her other projectiles.

Golem
Golem only spawns when a Lihzahrd Power Cell is inserted into a Lihzahrd Altar after Plantera is defeated.

Golem spits fireballs, fires off its fists on chains, and jumps around. When its head reaches half health, it starts shooting eye lasers. After its head is defeated, it becomes invincible and flies off of the body. If the fists are still there, they will punch rapidly. Its body jumps around and its head fires eye lasers, but no fireballs.

Empress of Light
This boss does not spawn on her own, and only spawns after a Prismatic Lacewing, a critter that spawns in the Hallow at night after Plantera is defeated, is killed. She follows a strict pattern of attacks, in this order: Prismatic Bolts: Creates a cloud of projectiles that fly at you after a short period. Dash Attack: Positions herself to the side of the player, before dashing at them. Sun Dance: Stops before firing 6 petal-like rays that slowly spin around her. This happens 3 times before the Empress starts moving again. Dash Attack Everlasting Rainbow: Releases a ring of 13 stars that slowly spiral out, then in. They leave behind damaging trails. Prismatic Bolts Dash Attack Ethereal Lance: Creates a swarm of swords that launch themselves at the player. Dash Attack Everlasting Rainbow This pattern repeats until the second phase.

After hitting half health, she will teleport above you and adopt a slightly different appearance. She then follows this pattern. Ethereal Lance 2: Four evenly spaced waves of swords. Prismatic Bolts Dash Attack Ethereal Lance (only enraged) Everlasting Rainbow Prismatic Bolts Sun Dance Ethereal Lance Dash Attack Prismatic Bolts 2: Spawns prismatic bolts in a clockwise pattern. Repeat until death.

The Empress enrages in the daytime. In the day, her attack all instantly kill the player with tens of thousands of damage. If every hit of damage is in the day, the Terraprisma will drop.

Duke Fishron
The Duke will not spawn naturally, only if you fish in the ocean with a truffle worm, a critter found in the Hardmode glowing mushroom biome.

Fishron has three attacks: Lunging from above five times, spitting out a bunch of Detonating Bubbles, and spawning a Sharknado that shoots out Sharkron projectiles. Under half health, Fishron will stop and roar was his skin gets darker and his eyes start glowing yellow. He will do loops while spewing Detonating Bubbles, spawns a Cthulhunado that fires even more Sharkron, and speeds up in his lunges. When the Duke falls below 15% health, he will become invisible, except for his eyes and the background turns dark blue. He will lunge once, then teleport and lunge twice, then teleport and lunge 3 times, then teleports and the pattern repeats until defeat.

Lunatic Cultist
This masked cultist only spawns after all of the Lunatic Devotees and Cultist Archers at the dungeon entrance post-Golem. They teleport around, using three attacks: A burst of three fireballs, a crystal of Ice Mist that shoots out six ice shards periodically as it flies, and a Lightning Orb that fires five bolts of lightning at the character. Under half health, they may replace an attack with two bursts of Ancient Light. In Expert, they can summon Ancient Dooms that fire purple projectiles in a cross pattern. After 5 attacks, it spawns duplicates of itself and a larger version of the pattern on the Celestial Sigil via a ritual. If a duplicate is attacked or you take too long hitting the real one, the remaining clones fly in formation with the real one, adding their shadowflame projectiles to the mix, as well as spawning a worm-like Phantasm Dragon. If said dragon is alive, an Ancient Vision will spawn instead.

The Moon Lord
The Moon Lord spawns a minute after either all four Celestial Pillars fall, or a Celestial Sigil is used.

This boss consists of two hands, a head and a chest-core. The hands and forehead all have damagable eyes on them that must be destroyed before the core reveals itself.

The hand-eyes can spawn Phantasmal Spheres that launch themselves at the player and explode, Phantasmal Eyes that act like the Servants from Eye of Cthulhu, or Phantasmal Bolts that fire directly towards you. The forehead-eye only opens every 20 seconds to fire Phantasmal Bolts, then a Phantasmal Deathray, then Bolts again before closing. When defeated, an eye detaches and becomes a True Eye of Cthulhu that uses the same attacks of all eyes combined. Its core cannot attack, and must be destroyed to beat the game.