- Since Scarecrow is in this film, that means it's in a DC universe, so why so much skepticism about the monster? Even if you remove actual magic from the equation, the pumpkins could've been creations of Poison Ivy or the Floronic Man.
- Fridge Brilliance: we don't know when in DC Comics continuity the movie is set. Jonathan Crane's Scarecrow debuted a good 20 years before either Ivy or Floronic Man. It could be a time before they either made their debut or at least were well known.
- In this specific incarnation, the Word of God didn't care about sticking to any single continuity, Scooby, DC, or otherwise, and just used what they wanted for Rule of Cool. But even as a general rule, DC characters have popped into HB shows for years and more recently vice versa. Trying to square any of that will probably give you a headache.
- Despite the Scarecrow, Gotham City, and Arkham Asylum being referenced as real, Bill Nye also called Aquaman fictional.
- Dr. Crane said that Velma reminded him of "the one person in [their] world he cares about". Just out of curiosity, who exactly is that?
- Since Batman from Batman: Brave and the Bold crossed over with the Mystery Gang a couple of movies ago, is this the same Scarecrow from that Batman continuity?
- If Scarecrow just wanted to watch the parade, then why did he attack it?
Headscratchers / Happy Halloween, Scooby-Doo!