Karl with a K

Karl with a K was a character who appeared in the Ben 10 animated series episode Scared Silly.

Description
A well-dressed, elderly man with lank grey hair, when he got hungry, Karl transformed into a bizarre green fish-demon with a taste for human flesh. In this form he had access to magical abilities such as force fields and energy blasts: these powers were channeled through a small orb which hung from his head in a similar way to the bioluminescent light of an angler fish.

History
The owner of a decrepit old hotel with his brother Carl with a C, Karl had been a man who dabbled in dark magic. One night his experiments went wrong however, and he was turned into the bloodthirsty creature that he was when encountered by Team Tennyson. This malfunction also killed his unwitting sibling, turning him into a ghost.

Years later, when the Rustbucket broke down near the hotel, the Tennysons decided to spend the night there. During the course of the evening, Ben was terrorised by a ghost, who eventually revealed itself to be Carl with a C, whose goal had been to scare the family into leaving before they were eaten by his brother.

At this point, Karl arrived and attempted to devour the trio, but Ben, in his Wildvine form, did battle with the demon, and was able to destroy his power globe, finally allowing the tormented man to rest in peace.