It isn't necessary to turn into a robot in order to beat round 5-3. All you have to do is a dance attack affecting 8 or more enemies. After Mr.Big leaves the scene, and before that little freeze that happens before every boss fight, take a jump and before Michael lands press the magic button. Keep moving while spinning to where there are more green guards until MJ starts dancing. Getting 8 or more guys dancing will make you win the battle. If you want to, press one of the buttons during the explosion, to make the star fall and turn you into a robot for no reason. In this stage, hitting any button during the fight causes the star to appears, so the trick is doing so BEFORE the battle begins, the jumping thing is just to get you more time to gather enough enemies to make it work. If you fail, just hit a button and the star will fall anyway.