>>48468886Pupitar is the real larval stage of the line. Tyranitar is the pupal stage for Pupitar and Pupitar reemerging and breaking open Tyranitar as M-Tyranitar. Think the Nincada line, and M-Tyranitar is like Shedinja with its back peeled open and flayed out like wings
A more serious answer, Tyranitar is probably just a lizard with a hide of a pachyderm. It probably still molts like a lizard though, and that would be what M-Tyranitar is supposed to represent. 
