Through the magic of Disney, Mickey takes Goofy back in time to check out some dinosaurs. It isn't long before Goofy witnesses something that will surely scar him, robbing him of the innocence that makes up such a big part of his bumbling charm. Mickey, hardened to the reality of nature's brutality, watches the slaughter as Goofy turns away in a vain attempt to erase the horror from his memory. It is futile, Goofy. You will never be the same.
Yes, Goofy, sauropods were the ultimate moveable feast, spending their lives dimly dreading the moment when some bored theropod decided he was a bit peckish, and might enjoy gnawing on a sauropod neck while it groaned in half-interested protest. Damn, I love the expression on bronto's face there. "Aggghhh, that's my neck, moron!"
Maybe he doesn't explicitly call Dimetrodon a dinosaur, but what else is poor Goofy supposed to think? It's included with the dinosaurs, and Mickey makes no effort to explain what it really is. So shame on you, Mickey.
The idea that the sail was used to help Dimetrodon "keep its balance in the swampy land where it walked" might be the dumbest hypothesis I've ever heard. If anything, I imagine it would make balancing harder... oh balls, I've fallen into Mickey's little trap. I'm not going to debate him. He'll just Gish gallop me and I'll never finish this post. So here's a pretty blue Stegosaurus. I'm out.