Fritz is a character from the movie Frankenstein, released in 1931.
Fritz is Dr. Henry Frankenstein's hunchback assistant who helps him to create the monster. Once the creature lives, Fritz takes sadistic pleasure in taunting the monster with a lit torch and a bullwhip. Dr. Frankenstein doesn't like this, but Fritz does this anyway. One day after the monster's latest Fritz-induced temper tantrums, Fritz goes down to the dungeon cell and tourtures the poor monster while giggling maniacally.
Later on, Dr. Frankenstein and Dr. Waldman suddenly hears Fritz screaming in agony, and realizes something is wrong. They run down to the dungeon where the scream was heard and when they finally arrive, they see that the monster was so mad at Fritz that he killed him by hanging him with his own whip.