Again, not a Marathon expert, but definitely worth a look.
Coleman Gailloreto (email@example.com) writes:
I found this in the Marathon scrap book, which can be found online. If you can't load the appropriate pages of the scrapbook, like me, then go to Hamish Sinclair's Marathon Story Page, and Go to "Fact and Puzzling Things about.."; Marathon Scrapbook, and you'll see a reference to a monster dropped from Marathon 2:
Sketch of the Zombie Pfhor, probably the coolest monster ever conceived for the game. All the upper part of the armor is gone, including the mask. The Pfhor skin is all covered with eruptions, like a case of chickenpox gone awry. The legs are deformed, swollen; the same goes for the arms. While the left arm is still recognizable, the right one seems like the cross between a slug and a piece of mucus. The shoulder is so swollen, the head is slanted to the left - yet the fighter is able to hold the staff with this arm.