Zorg commander

The Zorg Commander is a bipedal, skinless lizard-like creature. It's people, the Zorg, managed to create a large interstellar empire. After conquering enough planets, they decided to take a very long break by sunbathing from 10AM-4PM. The amount of sunbathing eventually caused their skin to fall off. After their disastrous vacation, Mental hired huge numbers of them and imported them from an unknown universe to act as disposable grunts. They now attempt to stop Serious Sam.

Unlike Zorg Mercenaries, Commanders have some skin left, which is the reason why they are commanders. Having skin also lets them lead Mercenaries into battle, wear underpants and not get blood stains on everything they touch. Having skin also means they're given a shotgun-like energy weapon as opposed to the weak two-shot burst laser used by the Zorg grunts