Have a large wyvern that flies through the air. Its attacks would consist of fireballs, swiping down to hit somebody, and other such generic wyvern attacks. But after it is defeated it will split into multiple smaller drakes that would have a buffed defense and buffed speed and hound players to the point that knockback would be useless. This would create a need for players to be more active in using their special moves and also a need for less stability (maybe?) so that if they do get hit they get knocked back.