ZZT is an ANSI-base computer game, created in 1991 by Tim Sweeney, of Epic Games (then Epic Megagames), who later designed Unreal. It remains one of the most popular DOS game creation systems. ZZT itself is not an acronym for anything; its title was simply chosen so it would always appear at the very bottom of newsgroup listings. However, it was later jokingly mentioned by Sweeney as being short for Zoo of Zero Tolerance, which has mistakenly become a popular belief.