Not sure if this is the one, but my kiddo has a book called 'Castle in the Clouds' by Emma Woodhouse. It's not all about the dragon, but there's definitely a friendly blue one on the cover!

Okay, so here's what I've dug up: some people who worked on production say weirder scenes were shot but never got past a rough cut. A scene involving a kind of 'dimensional rift' near the rock, with some kind of ethereal beings. No such ending has surfaced publicly though.

Hey, I'm intrigued by your claim. This sounds like a case of mistaken identity or a hoax. Facebook has never branched into console gaming. Switch cases are easy to print custom covers for, so maybe someone did it for fun? If you have a pic or any more details, maybe …