Mikey is not a combatant in the true sense. He is more of a punching bag or speed bump. He is equipped with neither fight nor flight reflexes, and will simply duck and cover while opponents wail on him.
Mikey is the target of a bonus round in which all players are racing to deal the most damage to him in 60 seconds. He will flap his arms and sniffle but Mikey will not fight back, and offers players a chance to practice their combat techniques or revel in the simple joy of pounding the snot out a goofy awkward looking middle schooler.
It is rumored that Mikey is a secret unlockable character as an achievement for losing 255 matches in a row. This version of Mikey, however, is Super Saiyan III and has maximum stats.