Professor Jantzen was a character from the Vincent Van Ghoul movie, Castle of Gummy Discharge. Van Ghoul hired an actor to play Prof. Jantzen when he was trying to start a reality show in which he scared his dinner guests, and Shaggy Rogers and Scooby-Doo were his first "victims."
His face has a half-broken mask over it, revealing red skin and a misshapen nose.
He threatens people with a rotating circular hand-saw and laughs maniacally.
Scooby-Doo! Mystery Incorporated
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- The character seems to be a parody of Prof. Jarrod in House of Wax.