Ben 10 season 3 episode 2 : Midnight Madness

While visiting a mega-mall, Ben and Gwen watch a hypnotist perform. Gwen volunteers Ben as a test subject, and the host, Sublimino, successfully hypnotizes him. When asked to act like an alien, Ben naturally turns to the Omnitrix and almost changes in front of the audience. Even though he is stopped by Gwen, the trouble doesn't end there. Sublimino is able to use those he hypnotizes to commit crimes in their dream state, and the alien-equipped Ben proves to be the perfect accomplice. Using Ben, Sublimino is able to steal parts to make a much bigger hypnotism device, this time hypnotizing everyone in the mall except Ben. Ben stops him as Wildvine and Sublimino is presumably arrested.