It's funny that it took 'til day 21 to reach the "dragons" in "Dungeons and Dragons". Granted, they might not be something every party faces. But not a single dragon fight I've been involved with is ever easy, and I could think of 10 off the top of my head. There were almost certainly more. When a critter is as big as dragons tend to be it has a lot of attacks. When a critter can fly and the players (frequently) can't, that adds another dimension to the battlefield, and another advantage on their side.
