What kind of collision made the moon?

It is thought the celestial body was created in a cosmic crash 4.5bn years ago

Corrected version:

It could so easily have turned out differently. About 4.5bn years ago the Earth is believed to have collided with another planet, Theia, resulting in the formation of the moon. A more glancing blow might have resulted in a hit and run" and a moon-less Earth; while a head-on collision may have blasted away much of Earth's mantle, leaving no atmosphere. Instead it seems to have been something in between, which eroded between 10 and 60% of Earth's atmosphere, but also left us with the moon.