1. Armadillos are most closely related to anteaters (not super-duper surprising) and sloths (much more surprising!).
2. There are lots of kinds of armadillos. The tiniest ones are called pink fairy armadillos and they're only five or six inches long from nose to tail. The biggest ones are five feet!
3. Armadillos caught leprosy from humans when European explorers brought the disease to the Americas in the 15th century and now a bunch have it and can give it back to us! What!? But that also means armadillos can be used to study leprosy in humans, so there's that.