RuneScape/Underground Pass

One of the Ardougne series. Here the player is introduced to the idea of lands beyond West Ardougne and they get a chance to fight the legendary Iban, alleged son of Zamorak. This quest can be very annoying for anybody who only got the minimum requirements in agility and thieving, 50+ thieving is strongly recommended (not least because it saves a trip through a maze) and it is also advised to get the highest agility level possible without dying of boredom (40+ will work). This quest can be very frustrating because there are so many agility obstacles where failing will result in having to walk through about half of the Pass a second time, the random text messages that pop up in the chat window don't really help either. Supposedly anyone who stays in the Pass for a long time will go crazy, the messages of "join us," "kill, destroy," and "Iban will release you..." will certainly push anybody with nerve issues to the edge of their seat.

Some more tips:
 * If you have a reasonable range level, bring range armour, a bow, and some arrows. The three greater demons in the quest can be ranged/maged from the bridges but range works better as earlier on in the quest you will need to face melee monsters and mage armour won't help against those.
 * If you dislike spiders, you'll have to fight a giant one at some point. Play on low detail with the camera up all the way so you won't have to look at it.
 * Bring lobsters or swordfish (sharks if you can afford it), fill up your whole inventory, you're going to need every last one of them.
 * Bring prayer potions!!!