Dimetrodon

The Dimetrodon is a three-part fossil that can be donated to the museum in and.

In Wild World
"It lived early on, when dinosaurs first began roaming the earth, wot? And actually, to be quite accurate, it's not even a real dinosaur at all! As we know, dinosaurs were cold-blooded and could not change body temperature. But the dimetrodon could! It used its distinctive back to control heat! For this reason, it is considered what we call a "mammalian reptile," wot? Ah. Hoo. Yes, sorry. I got rather blabby, there. I got heated up, hoo!"

In City Folk
''"...And with that, the dimetrodon is complete! Hoo, what a spectacle! The dimetrodon was from a period early in the history of the dinosaurs, eh wot? In point of fact, it's not even a real dinosaur! That's because it could regulate body temperature, unlike other dinosaurs. The dimetrodon did so by using its distinctively shaped back... Indeed, and that is why it's considered what some call a 'mammalian reptile'!"