The Bald zombie is a zombie with a distinct red tinge covering its body. It looks like a humanoid of head-to-toe fully exposed muscle. Bald zombies are first encountered on the first level, The Gas Station, introducing the SMG and its usefulness against weaker enemies. Bald zombies are unique in that they are killed in one shot by nearly every weapon, but draw strength from their sheer numbers and unreduced speed.
It may be speculated that the reason they are weak and appear as they do is that they are corpses that have been rotting over a long period of time as opposed to humans who became infected relatively recently, resulting in the lack of flesh covering their bodies.