What is "ixitxachitl"

In the Dungeons & Dragons role-playing game, ixitxachitl (pronounced ish-it-SHACH-itl, although iks-it-ZATCH-i-til or ik-zit-zah-chih-tull are both used) are a race of intelligent, aquatic beings that resemble small manta rays with barbed tails. They have an evil disposition and worship evil powers. They love to hunt marine humanoids, and then sacrifice or devour their catch.