Gahan Wilson's The Ultimate Haunted House

The Ultimate Haunted House is a computer adventure game created by Gahan Wilson. In it, you travel around a house in search of thirteen keys. You will encounter various creatures as you pass through the haunted houses's thirteen rooms, collecting various objects and putting them into your luggage. Having said that, you must leave the house before thirteen o'clock, or else you'll have to stay there forever.

It contains many clever voices and an opening tune of "Monster Mash".

Various characters in the game include Frankenstein, a vampiress, a two-headed monster, a mad scientist, and a kid (transported there by the mad scientist's lab ray). Gahan Wilson is a ghost in the game, but there are two Gahans: one good, one evil. Supposedly there is a way to find out which is which. The thirteen rooms include a menagerie, kitchen, foyer, torture chamber, the monster lab, the screening room, the game room, a library, and attic, a bathroom, a basement hallway, a music room, and an art gallery.