Giant leech

The Hoover Dam Scum Pits are occupied by giant leeches that swim in and out of the large holes in the ground where the power generators used to be. These leeches are the size of a full frown pot-bellied pig and have been known to suck out enough blood to kill a super mutant. These critters are very slow and will attack on sight. They also attack the giant albino rats in the Scum Pits.