Ok i found this out just now when your at dexters diner and u find the droideka(droid that can curl into a ball and roll around) go outside of dex's diner and into the parking lot make sure u have a gun character as an alternate player switch into the gun char and run so the droideka follows and curls into a ball once u do this and he's rolling quickly press "Y" to switch bodies and once ur the droideka and u are coming out of ball form quickly switch back to the gun char the droideka will now follow u without becoming a ball but he will be slow to fix that just switch bodies again and then switch back he will now keep up with you and stay in walking mode with a sheild! but becarefull if he bumps into another character he will return to normal also watch out for corners and walls! have fun!