We hit upon this question a few months ago (Sean's a few months older than Mac, and has a big brother). We actually tried the limb approach, combined with the fire. But after much consideration, Sean decided that he could tell the difference because "Dragons have Knights". Needless to say, he was disappointed when we visited StoryLand this summer, because although there were knights at Cinderella's Castle (if asked, he will tell you that Cinderella wasn't home, when in fact he ignored her), there were no dragons. Too bad it wasn't Sleeping Beauty's castle!