Ben 10: Alien Force(2008)

Season 2

15-year-old Ben Tennyson chooses to once again put on the Omnitrix and discovers that it has recalibrated and can now transform him into 10 brand-new aliens. Joined by his super-powered cousin Gwen Tennyson and his equally powerful former enemy Kevin Levin, Ben is on a mission to find his missing Grandpa Max.