Fake floor

An illusio-pit is a pit sector at least 128 units below its surrounding floor with no texture on the walls of the pit. The technique is often used in non-joke WADs to raise floors instantly, suddenly revealing enemies.

The name originated in wow.wad, an infamous and controversial WAD by Paul Thrussell which was his only release in 1999. The level consists of a room with a pit which has its walls untextured. A Cyberdemon is placed inside the large inescapable pit while there is a hanging torso. The player is given a BFG9000 and several other items, and has no exit. The text file explained the pit as follows:


 * A cyberdemon has escaped from a lab, where they are trying to find his weakness. He was injured by a marine, which was made short work of, and he was trapped inside a illusio-pit.

Illusio-pits have been used in parts of other Joke WADs such as Mock 2: The Speed of Stupid and The New Adventure.