Boo Brigade Return

From the Super Mario Wiki

Boo splitting into multiple smaller Boos, while using Boo Brigade Return.

Boo Brigade Return is the Defensive Power Shot used by Boo in Mario Power Tennis. Boo achieves spinning around, becoming bigger, until it splits up into many smaller Boos, searching of the ball to hit it back to the opponent. Curiously, the Boo brigade does not show the "real" Boo with the glowing racket, but it appears once it finds the ball.