Evil Dave's BASEMENT OF DOOM is a dungeon that exists in the basement of Evil Dave's mother's house in Edgeville. The only inhabitants of the dungeon are Evil Dave himself and a swarm of Hell-Rats.
Players have to visit the dungeon during Recipe for Disaster: Freeing Evil Dave to obtain spices for, what Evil Dave calls, his "EVIL STEW OF DOOM". The player must use their cat to kill the hell-rats. The hell-rats will drop special coloured spices that they had stolen from Evil Dave's mother. The spicy stew with the correct amount of each of the four spices is needed to unfreeze Evil Dave from the Culinaromancer's spell.
Players may visit the dungeon after starting the subquest to obtain more spices to use on their own stews. Spicy stew is used to try to get boosts in various skills. The type of skill boosted depends on the colour of the spices used.
A player's cat is likely to turn into a Hellcat in the dungeon during the subquest. A hellcat can be turned back into a normal cat at any time by feeding it a bucket of milk. Players can also change their cat into a hellcat after the subquest by catching a few hell-rats. A cat at any stage of growth can become a hellcat, and a cat that has become a hellcat will continue to age as normal. While it is impossible to convert an overgrown cat into an overgrown hellcat, since overgrown cats cannot catch rats, players can get an overgrown hellcat by allowing a hell-kitten or adult hellcat to age into an overgrown hellcat. Players who have completed Rat Catchers can also get wily and lazy hellcats, either by using their wily or lazy cats to catch hell-rats, or by taking an overgrown hellcat to Felkrash and having her train it.