What happens when you skip a rock on a frozen lake? The "coolest sound ever!"

YouTube filmmaker Cory Williams was walking around Alaska when he found a frozen lake. He picked up a rock and attempted to skip it across the frozen lake.

The result blew Williams’ mind.

“This is the coolest sound I’ve ever heard!” he screams in the video (the fun starts at 3:40).

The pinging sound is created by the vibration of the ice caused by the rock.