What If Uncle Ruined Scooby-Doo:
Scooby and the Gang have trapped the demon. "Now, let's see who he really is…" But before Velma could unmask him, Uncle opens a portal and the demon goes through. "What did you just do," asks Velma.
"I banished the demon," says Uncle.
"But he wasn't a real demon, he was a real estate scam artist," says Velma, "that's what the clues all revealed!"
"Oh… Uncle is sure he's fine!"
...
The fake demon is now surrounded by the Demon Sorcerers. "Um… I'm not a guy in a costume?"
...
"Scooby-Dooby…" Scooby gets possessed. "Shen Du!"
The End