R.L. Stine 
Body Switchers from Outer Space 

Will the Spill is a total klutz. Hed give anything to be Chadthe most popular kid in schooljust for one day. Chad never trips, or falls, or drops anything. Then Will gets his wish. Chad says hes got a body-switching machine. And he wants to switch bodies with Will! Will decides to do it. And it works. He loves being Chaduntil he finds out Chad’s horrible secretand realizes hes trapped in Chad’s body forever!