Doom · PC · 1993 · Cheat Code
Effect: Allows the player to walk through walls and solid geometry.
Doom's no-clipping cheat has a two-version history: in the original 1993 Doom, the code was IDSPISPOPD — a reference to a running joke in the id Software fan community about "Smashing Pumpkins Into Small Piles Of Putrid Debris." In Doom II (1994), it was simplified to IDCLIP. The ability to phase through walls was used by players to explore out-of-bounds areas, find map geometry secrets, and later became a staple technique for speedrunners studying level layouts.