Rogue is a dungeon crawling video game first developed by Michael Toy and Glenn Wichman around 1980. It was a favorite on college Unix systems in the early to mid-1980s, in part due to the procedural generation of game content. Rogue popularized dungeon crawling as a video game trope, leading others to develop a class of derivatives known collectively as "roguelikes". For example, it directly inspired Hack, which in turn led to NetHack. Roguelikes have since influenced commercial games outside the genre, such as Diablo.