I.M. Werfzel

 I.M. Werfzel is Plumber stationing on Earth who first appeared in Rad Monster Party.

Ben 10: Omniverse

 * Rad Monster Party (first appearance)
 * Final Countdown (cameo)

Etymology
I.M. Werfzel is a combination of Michael Dorn's two famous roles. First being I.M. Weasel, from I Am Weasel and the second being Worf from Star Trek.