My favorite prehistoric creature, a hypercarnivore apex predator (and one of the first vertebrates to have sex - really), is our orca-sized friend Dunkleosteus terrelli. Now he's reached the apex of 21st century fame:
His own Facebook Page
Intended to be a respoitory for information - schaolarly, popular, and entertainment - for all thing Dunkleosteus, not to mention his relatives and the Devonian era he rules.
Visit, like, and have fun!