Yo Bro.

From the Super Mario Wiki

A Yo Bro.

Yo Bros. are an enemy encountered in Woohoo Hooniversity during the events of Mario & Luigi: Superstar Saga. The enemy was vaguely Koopa-like and sported a magician's hat and cape. Yo Bros also hold two yo-yos, one red and one green. Whichever yo-yo it spun indicated which Mario brother it would attack. It could also fake out, but the way to know if he is really attacking is that the "spinning" sound only played if he really was attacking. He, like other Koopa-like enemies in the game, were healed by fire.

[edit] Trivia

• Unlike most creatures in the Hooniversity, which were themed after "smart" items, such as robotics and vitamins, the Yo Bro. resembles more of a "street" look, which suggests these may possibly be students Cackletta transformed.