The hagfish is a slime-emitting ocean-dweller that's remained unchanged for 300 million years--and it shows. It has a skull (but no spine), velvet smooth skin, and a terrifying pit of a mouth that's lined with rows of razor-sharp teeth.
Did you know dinosaurs had wishbones? Yup. When this guy was restored for display purposes, it was noted that his "furcula" was original. We think if you're pulling on a dinosaur's wishbone, you'd best get your wish.