This is another giant scorpion. It grew to the size of the Brontoscorpio but with a smaller stinger and every bit as voracious. The Plumonoscorpius was terrestrial.(source)
You could call the Cameroceras, the ancient ancestor of octopi and squids. It had a 12 meter shell that made it move slower but it was powerful enough to take down ancient predatory fish and sea scorpions.(source)
No one ever wants to come face to face with a crocodile, especially a hungry one. They are pretty scary. They have mastered the art of hunting and like to stay in the shallows of rivers and lakes where they grab prey from the shores. They rarely venture far from water and that’s a good thing.
The Kaprosuchus however is an all terrain animal. Its name means “boar crocodile’ due to its long chompers. This six meter long killing machine could do what a crocodile can do but better. It could wait in water and attack but could also run on land. No luck for any living thing whether in water or on land. Oh, and dinosaurs presented no challenge- it could kill them too!(source)
These days snakes are pretty small. The green anaconda is the largest so far and the reticulated python is the longest. The Tinatoboa would have feasted on them so fast. It measured over 12 meters lengthwise and was the size of a T.rex. It ate mostly giant crocodiles and turtles and lived right after the extinction of dinosaurs but ruled the earth just like they did.(source)
10. Livyatan melvillei
You’ve heard of the megalodon. The giant shark everyone is scared of because it has teeth the size of a hand. Well, this whale trumps it.
The Livyatan got its name from the biblical monster, you know, the one God had to kill? (It’s also in ‘Moby Dick’.) Its teeth were a foot long, grew larger than the megalodon and hunted anything in its wake. Beaked whales, baleen whales, porpoises, dolphins, sea turtles, sharks, sea birds and seals were all part of its diet.(source)