Before the extinction of the dinosaurs, a velociraptor egg was layed deep into the ground. The egg hatched much

Raptorzilla compared to a 5-foot tall man.

after all dinosaurs were cleared from the world, and it hatched an extremely abnormally large velociraptor. He was still alive at the time that humans began building cities. He rampaged through the cities, killing almost everyone he saw. During his rampage, he was dubbed Raptorzilla due to his size. The people with weapons that allied up against him scared him off, and he fled to live in the thick jungle nearby. Weapons don't hurt him, but make him angrier.