Ben 10

Max Tennyson, or Grandpa Max as his grandkids call him, is Ben's grandfather. Though his age hasn't been mentioned yet, he seems to be in his late 60's. With a keen sense for adventure and a strange taste in food, Max always ends up taking the kids (and their taste buds) on interesting trips. As soon as school lets out, Ben looks forward to going on a traditional summer road trip with Max. Much to Ben's dismay, he discovers that his cousin Gwen (whom he dislikes) is joining them, as well. Max was in the army (among other things, it seems) and has been through his share of scrapes, so he takes his grandson gaining superpowers in stride, and he supports Ben in any way he can. Ben and Gwen were not aware of this at first, believing him to have been a plumber. They began questioning this after several incidents in which he displayed knowledge and skills that a plumber would not normally have everything from military-style hand signals to a working knowledge of nuclear reactors. Max and Vilgax are also old enemies, with Vilgax even going so far as to call Max "a thorn in my side." In actuality, he was indeed a plumber, but not the kind that Ben and Gwen thought he was. He was part of a government organization called "The Plumbers" which dealt with extra-terrestrial, paranormal, and other situations that others could not. Their base was beneath Mount Rushmore. The group was disbanded shortly after Max defeated Vilgax for the first time, suggesting that Vilgax had been largely responsible for the various incidents they dealt with.