Doom (1993 video game)
The ability for others to create custom levels and otherwise modify the game using WAD files turned out to be a popular aspect of "Doom". Gaining the first large mod-making community, "Doom" affected the culture surrounding first-person shooters, and also the industry. Several future professional game designers started their careers making "Doom" WADs as a hobby, among them Tim Willits, who later became the lead designer at id Software.
Cyberdemon
The Cyberdemon is a fictional character in the "Doom" gaming-franchise by id Software, where it was introduced in the first-person shooter game "Doom" in 1993. It has appeared in several other id games, including all main-line "Doom" sequels, "Doom RPG", and "Wolfenstein RPG" as the Harbinger of Doom, along with other related media. The Cyberdemon became one of the most iconic characters of the "Doom" series along with its protagonist, the "Doomguy", and is often described as one of the most memorable bosses in video gaming history.