Captain Obvious Reveal: Alicia Silverstone's character Heather Jasper-Howe being the Big Bad. You have to admit, a famous celebrity playing a supporting character in a Scooby-Doo movie would definitely tip a few people off.
One-Scene Wonder: The Cotton Candy Glob. He's not a villain from any Scooby-Doo cartoon in the past, but nobody could ignore his single scene.
So Bad, It's Good: While the film isn't exactly Oscar bait, a lot of people enjoyed some of the genuinely good attempts at praising the Scooby-Doo lore and capturing some qualities from the classic cartoon.