Frank is a man who lived secretly at Castle Von Dinkley
He has white eyes, greenish skin, and an oddly-shaped head like a Frankenstein.
He can act menacing, but he is simple-minded and easily stopped with a reprimand like "Bad Frank!"
Scooby-Doo! (DC Comics)
He tried to scare potential heirs away from the castle as the Frankenstein Monster of Castle Von Dinkley, because Victor Von Dinkley convinced him that otherwise he would lose his home. (Family Monster)
- He is one of the few culprits who could appear as a monster without a mask.
- Velma found a clue about him in an old laboratory in the castle, but it is never revealed whether he was a monster brought to life by the old Victor Von Dinkley (namesake of the current one) or just a deformed normal man.