The Mazacoatl, “deer snake”, is a great serpent that lives in caves on steep mountains and cliffs. It has antlers on its head and a rattle on its tail. It never leaves its lair, as it can draw in with its breath rabbits, deer, and humans alike.
Nuttall, Z. (1895) A Note on Ancient Mexican Folk-lore. The Journal of American Folklore, v. 8, no. 29, pp. 117-129.