Ben 10: Alien Force, Season 1

Gwen:
Grandpa Max doesn't have anything to do with this, does he?

Kevin:
Nope.

Gwen:
So that badge belongs to the Heatblast guy. Where do you think he got it?

Kevin:
He doesn't act like a Plumber. He's probably just a Plumber's kid.

Gwen:
Why would a policeman give his son a badge?

Kevin:
To keep real Plumbers from arresting them for interplanetary trespass. A badge is better than a passport.

Gwen:
I'm not following.

Kevin Levin:
Heatblast Jr. is probably part human. Human's with alien ancestors are actually pretty common. Most of them have superpowers.

Gwen:
Common?

Kevin:
Well, yeah. That's what you are. You get your powers through your grandpa. I thought you knew.

Gwen:
(scoffs) I get my powers from magic talismans and books.

Kevin:
(laughs) Yeah right. Magic.