Aaaah, explains the nagging differences. In a rules-consistent way. That has nothing to do with any theory that I as a player would have though of, since those all revolved around [sblock]Xykon somehow being related to the fakes.[/sblock]
That's one of my bugaboos regarding the Mohrg is how they're always shown as skeletons. The description of the critter describes them as really gaunt corpses. Nearly skeletal. Skinny zombie material. Not bones with a wad of chewing gum in the middle.