WAD stands for 'Where's All the Data?' Immediately after its release in 1993, Doom attracted a sizeable following of players who created their own mods for WAD files-packages containing levels, graphics and other game data-and played a vital part in spawning the mod-making culture which is now commonplace for first-person shooters. 'Doom WAD is the default format of package files for the video game Doom or its sequel Doom II, that contain sprites, levels, and game data.