Shotgun Guy/Doom 64

The Shotgun Guy makes an appearance in DOOM 64.

Background
The Shotgun Guys of DOOM 64 are reanimated carcasses of those from DOOM, reanimated by the Mother Demon. They are made from systematically altered dead carnage remade back into corrupted living tissue. The mutations were devastating. The Demons have returned stronger and more vicious than before.

These guys may look like your old buddies, but now they're nothing more than bipedal maggots. They are much like the Zombiemen, except these guys are meaner, and tougher. These walking shotguns will provide you with a few extra holes if you're not careful.

Interestingly enough, they use the sprites of the Zombiemen, but with a different palette applied (white/gray shirt) to change their suits to look more like the original Zombiemen, making both monsters extremely difficult to differentiate in the game's darkness. In this game, Zombiemen have green pants, while Shotgun Guys have gray ones. They first appear in MAP01: Staging Area.