Banana Ball

Banana Ball is the name of the Special Ball that Donkey Kong uses in Mario Superstar Baseball. While pitching, DK will toss a Banana at the batter. This will act as a Boomerang, as it will curve greatly when thrown, and then curve straight past the batter. Hitting this ball requires careful concentration, as it curves.

If DK is batting, he will also hit a Banana out into the field, which will also curve greatly, as it slices through the field. This is still hard to catch, but it it not necessarily impossible to catch the Banana Ball. It is a direct copy of Diddy's Boomerang Ball.

Mario Super Sluggers
The Banana Ball returns in Mario Super Sluggers, but it's exclusively given to Diddy Kong, while Donkey Kong gets a different Star Pitch. Like in the prequel, this Star Pitch will make a curve, which can mess up batters. Normaly Righties have a harder time hitting this special pitch.

Trivia

 * The player must obtain a King Banana Power-Up in Challenge Mode of Mario Superstar Baseball before being able to use this move.