Cretaceous-Paleogene Extinction (Reptilian Revival)

Summary
The Cretaceous-Paleogene extinction event (K-Pg extinction) was a major near-extinction-level event which happened approximately 66 million years BCE.

The event was caused by a shower of large asteroids entering the earth's atmosphere at various locations. Scientists speculate that the asteroid was initially 10-15 kilometers in diameter and struck the moon during its approach, causing the Mareluna crater towards the north pole of the moon.

Effect
The asteroids effectively wiped out at least 80% of the animal population at the time. Several dinosaur species survived this event such as the Hypsilophodon, Velociraptor and several other smaller species.