Professor Krassman is the world's leading authority in the rapidly-growing field of mind control in frogs.

Krassman is hired by Doc Hopper in The Muppet Movie to force Kermit the Frog to appear as a commercial spokesman for Doc Hopper's Frog Legs.

The result of many late nights at his laboratories in Cologne and Düsseldorf, Krassman's latest achievement is an imposing device used to perform an electronic cerebrectomy--a process by which a frog's brain is reduced to guacamole. But due to the timely intervention of Miss Piggy, (whom the professor really should not have insulted) Kermit's gray matter is saved and Krassman becomes a victim of his own machine.

In typical mad scientist fashion, Krassman is prone towards maniacal laughter, taking great joy in his work. When others join in, however, he curtails it, stating that "I detest the surfeit of provincial laughter."

Krassman's lab coat has "Prof" emblazoned on the back. This is an allusion to Mel Brooks' role as Governor LePetomane in Blazing Saddles, the back of whose suit coat was clearly labeled "Gov."