OK, this is just one example, but I want to know about the general case.
What would cross-universe dragons be like? e.g. the dragons of the world of Harry Potter and the dragons of Anne McCaffrey's Dragons of Pern.
I can't see how this could be a good question on the main site, but I've love to see it discussed. Would it be suitable as a chat room event theme, as a possible way to draw in new contributors?