Dr. Jekyll is a failed scientist turned thief.
He is a middle-aged Caucasian male with brown hair and wears glasses. He wears a white lab coat and blue pants.
He acted like he was the victim of one of his failed experiments, but this was only a cover. In reality, he was callous as he tried to pin the blame of his thefts on his housemaid, and as the Ghost of Mr. Hyde, he acted like a mad scientist, strapping Shaggy Rogers down and planning to use him as a guinea pig for a frog potion he was purportedly putting together.
He claimed to have created a vitamin drink that would last a lifetime, but the experiment went awry and he transformed into the ghost of Mr. Hyde (supposedly the ghost of his own great-grandfather's Mr. Hyde monster). In reality, all of his experiments had actually been failures, so he decided to turn to a life of crime.
Scooby-Doo, Where Are You!
After one of his robberies, the Ghost of Mr. Hyde hid in the back of the Mystery Machine (under a beach blanket), and was soon discovered by the gang, who followed him to Dr. Jekyll's mansion they found nearby, after the monster escaped. He told them the phony story about the vitamin formula, and then proceeded to plant a bunch of fake clues, incriminating Helga, his housemaid, as the ghost. But they were still able to solve the mystery and catch Dr. Jekyll. The important clue which connected him were the suction cups he used to scale the buildings, which Helga didn't need due to her being an former circus star. The gang left him to be taken into custody by the sheriff.
- In the Game Boy Color version of Scooby-Doo! Classic Creep Capers, he says it was his father.