Isle of the Ape is a Dungeons & Dragons adventure by Gary Gygax, set in Greyhawk. Much like Tomb of Horrors, it is an extremely difficult module intended to test highly-skilled players with max-level characters.
A war between the forces of good and evil is imminent. But a powerful artifact of good, the Crook of Rao, has been lost upon the island of the title. But this is no tropical paradise. Created by the mad god Zagyg, the island is pretty much a self-contained Death World. It is filled with huge, violently hostile wildlife; the heat and humidity quickly degrade and destroy equipment and supplies; and diseases are so virulent that they infect characters immune to diseases. Oh, and there's a cannibal tribe so powerful that they could probably take down a small army in a normal setting. Making things worse, Your Magic's No Good Here. A slew of spells that would normally allow characters to mitigate or bypass the dangers of the island either don't function at all, or have their effects severely curbed.
Lording over all of this is Zagyg's prized pet, Oonga, a King Kong Copy with a power level comparable to some gods.
Summoned by one of the world's most powerful mages who barely survived a short stay on the island, your party is tasked with the nearly impossible mission of getting in, finding the Crook, and somehow escaping alive.
Tropes:
- Cannibal Tribe: The Kawibusa, who dominate the tribes of nearby islands due to how tough their environment has made them.
- Closed Circle: The isle and its surrounding island chain are actually in a Pocket Dimension. Once the party enters the region, they can only leave through the exit portal.
- Evil Cannot Comprehend Good: In the Kaizo Trap, the demon masquerading as a good wizard tries to politely congratulate the party and request the Crook, but cannot avoid peppering his speech with condescension and back-handed compliments, which is a clue that things aren't right.
- Giant Flyer: Flight spells work, but are almost suicidal to use due to all the giant flying monsters in the skies.
- Have You Seen My God?: Clerics still receive spells, but ones that would let them communicate with or seek advice from their deity don't function.
- Human Sacrifice: The Kawibusa think Oonga is a god, and offer captives to him in a ceremony. He's not and doesn't even understand that they're worshipping him, but is happy to stop by for a free snack.
- Hungry Jungle: Pretty much the whole point here. It will definitely eat PCs alive if they're not at the top of their game (and probably even then.)
- Kaizo Trap: After finding the escape, unless the PCs take a specific action that is only vaguely hinted at, they end up in what appears to be a high council of the good guys, with a chief wizard asking them to hand over the Crook. They're actually disguised demons trying to steal it away, and are powerful enough to likely slaughter the party if they refuse. There is a way to be rescued, but the action required has no clues anywhere.
- King Kong Copy: Oonga, who is almost impossible to kill due to his resistances and regeneration, and hits hard enough to slaughter a high-level party in a few moves. There are also several "lesser" giant apes that are still basically kaiju in their own right.
- MacGuffin: The Crook of Rao. It's stated to be this super powerful and important artifact, but what it actually does is never detailed even to the DM and has no bearing on the adventure. When in the Kaizo Trap at the end, a player can raise it and call out for help to be rescued (if they think to,) but it's not clear they're actually invoking any power of the Crook itself.
- A Mind Is a Terrible Thing to Read: The party can end up inside Zagyg's mind. The problem is, he's insane, and his thoughts can drive party members permanently mad. However, his mind also has some vital clues for surviving and completing the mission.
- The Plague: There are several virulent and deadly diseases you can catch, and they laugh at disease immunity.
- Pocket Dimension: The island and its region are actually this. You can sail into it from the Greyhawk world, but can't leave unless you find the exit. Which is right inside Oonga's lair. Have fun with that.
- Your Magic's No Good Here: A lot of spells that would let a party "cheat" their way past the dangers (such as teleportation) are disabled. Also ones that would let them seek information about the island.
