Quarjakl

The animal that formed into a dragon over several millions of years because it had some major flaws---Its legs were flippers-sometimes its fire breath would backfire and go straight into its stomach-and after a couple of years, its wings would be too small to bring up the whole animal.

It fed on small flys and grass as a youngling, and as an adult it would go after any other large dinosaur.
-was an omnivore
-had scales
-had a very strong tail used to kill other animals
-its claws were as tough as diamond