Under the sea during the Late Cretaceous Period, around 66 million years ago, Mosasaurus hoffmannii pursues an ammonite for lunch. Stretching between thirty and sixty feet in length, this massive predatory sea lizard would have most likely been the apex predator of the Late Cretaceous oceans. Its closest living relatives would be snakes and monitor lizards such as the Komodo dragon.

If you’re wondering what those pink things with the tentacles in the lower right corner are, they are rudists, an order of molluscs that would have dominated reefs during the Cretaceous Period. They died out approximately at the same time as the mosasaurs and the non-avian dinosaurs at the end of the Mesozoic Era.