The Mokonas! I'm not sure what kind of creature they are, but they're prevalent in CLAMP, like Magical Knights Rayearth (first appearance), xxxHolic (black Mokona) and Tsubasa (white Mokona). They're heavy drinkers and the black and white Mokona have the ability to communicate and send objects between them. Oh, and the white Mokona can transport people to different dimensions. Tres cool. They win the hearts of fans in whatever series they appear in.