Armadillos are New World placental mammals with a leathery armor shell. The word armadillo means “little armored one” in Spanish. The Aztecs called them āyōtōchtli, Nahuatl for “turtle-rabbit”.

[F]our genetically identical offspring are born, the result of one original egg. Because they are always genetically identical, the group of four young provides a good subject for scientific, behavioral or medical tests that need consistent biological and genetic makeup in the test subjects.

This is the only reliable manifestation of polyembryony in the class Mammalia, and not in all armadillos.

Seems like they’d make a badass supervillain team for the Teenage Mutant Ninja Turtles to face. Just saying.

Via Wikipedia.