Shotgun Guy

The Shotgun Guys, sometimes referred to by different names by different sources, are recurring enemies in the DOOM franchise.

Doom 3
See Z-Sec

Doom 64
The Shotgun Guy makes an appearance in DOOM 64, but interestingly enough, they use the sprites of the Zombiemen, but with different palettes applied to change their suit to 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 grey ones. They first appear in MAP01: Staging Area. As with Zombiemen, they are left-handed.