IDKFA The meaning of this is unclear It is variously described as ID Kicks Fucking Ass or ID Killer Full Ammo I went back to the original Doom source ftp ftp idsoftware com idstuff source doomsrc zip to see if I could resolve this Indeed the comments in st stuff c give definitions for these cheat codes IDFA is commented as fa cheat for killer fucking arsenal IDKFA on the other hand is commented as kfa cheat for key full ammo So it looks like ID Kicks Fucking Ass is apocryphal MOTHERFUCKENKIWIBASTARD Why do people keep removing MOTHERFUCKENKIWIBASTARD It is a real cheat code I have tested it myself Yeah it s real and famous among Amiga users Definitely should stay