If you think our creatures today are strange and terrifying, these 8 pre-historic creatures will shock you and make you happy you weren't alive when they roamed the Earth.
1. Mosasaurus
This sea monster grew up to 60 feet and weighed up to 5 tons. It existed in the Cretaceous oceans before it became extinct. Fun fact: The Mosasaurus was featured in the movie Jurassic World.
2. Dunkleosteus
These creatures were positively nightmarish sea monsters which had heavily boned "armor" around their bodies. Their powerful jaws made them the most fiercest and feared creatures in the seas.
3. Titanoboa
This snake's fossil was found to be more than 40 feet long which marks it as the world's largest snake.