Ahuizotl

An ahuizotl was a semi-aquatic aberration that mimicked voices and preyed on unwary travelers. It resembled a doglike monkey and had a clawed hand on its tail.

Description
Although the ahuizotl was large, it resembled a monkey with a long canine snout and teeth and a long feline neck, and it was capable of submerging its entire body beneath as little as three feet of water. Its long, prehensile tail had a large, muscular, clawed hand with which it attacked its victims. Its forelegs were like a monkey or ape's, articulated for knuckle-walking, while its hind legs were similar to those of a dog. Its fur was mostly sleek and brown, with white hair on its chest, belly, and under legs. It also had brown and white facial patterning similar to a ring-tailed lemur or raccoon.

Combat and abilities
Excellent swimmers, ahuizotls lived in lakes and preyed on people who came too near the banks or who ventured out on boats. Submerging itself out of sight like a crocodile, an ahuizotl would raise only its snout out of the water, through which it could mimic voices calling for help. Its attack always began with its tail, with which it drowned its victims. It's tail also possessed a blinding strike whereby it could permanently blind its opponents. Once drowned, victims were brought down to the depths of the lake, where the ahuizotl ate its favored parts, the eyes, teeth, and fingernails.

In addition to mimicry, it was intelligent enough to be able to speak Common on its own as well.