It’s not clear where this happened. A mountain biker set up his phone to take videos of himself going down a trail. In one clip you see him riding by, and then you hear him saying “hey, hey, hey”… like he’s trying to warn someone.
The warning was to a BEAR that is following him back up the trail. The guy does the “look large” defense tactic by holding his bike over his head, and it works. The bear retreats.