Peneteius was a lizard that lived toward the end of the reign of the dinosaurs.  It was different from all other lizards in that it had molars, much like the molars of a mammal.  Although there were other heterodont lizards, Peneteius was unique in some key ways.  Much like mammals, but unlike other heterodont reptiles, Peneteius' uppers and lowers did not grind on each other.  This made another unique feature possible – its teeth did not have to be constantly replaced.  This is dissimilar to dinosaurs and other reptiles which continuously replace their teeth as they wear out from grinding against each other.  Also, its uppers were different from its lowers, and the cusps of its molars are more mammal-like than any other reptile.[1]  Could it be that angels or aliens mixed lizard DNA with mammal DNA, thereby giving these lizards molar teeth?  Click to read more about fossil frankensteins.