In the Glee episode "Bad Reputation", none of the following characters perform "U Can't Touch This" during the episode: Rachel, Finn, Kurt, Mercedes, Santana, Puck, Quinn, Artie, Brittany, or Sue.
Rachel, Finn, and Mercedes did not perform the song 'U Cant Touch This'. We apologize for any confusion that may have arisen due to the song being associated with the show. We hope you continue to enjoy the rest of the episodes and the amazing performances our talented cast has to offer.