Bubblainian volleyball coach
From the Super Mario Wiki
The Bubblainian volleyball coach is a coach thats hosts the Beach Volleyball minigame in the Seaside Kingdom in Super Mario Odyssey. When the minigame is played, he serves the ball and hits it back when the players returns it. If the player uses Cappy to spike the ball he spins and drops a varying amount of coins. Once the player returns the ball fifteen times, he gives the player a Power Moon, and gives another if the player returns it one-hundred times.