Rainbow Swing
From the Super Mario Wiki
Rainbow Swing is Yoshi's special swing in Mario Super Sluggers. Yoshi will lay a Yoshi Egg and hit it. It will bounce around the field in a similar fashion to Waluigi's Liar Swing, and it will have a rainbow trailing after it, hence the name. Once the egg comes to a stop after two or three bounces, it will disappear and the ball will take it's place.
