Donkey Kong Banana Bunch

From the Super Mario Wiki

Donkey Kong Banana Bunch is a mini-game in Mario Tennis for the Game Boy Color. It involves the player hitting a ball (As the game is tennis). The player is Donkey Kong, and scores points everytime he hits a Banana with that ball. The bananas are on panels. They move constantly.

One banana is equal to one point, while 3 bananas in a bunch is equal to 3 points. He can keep playing until he misses.