People think he's dangerous, but I don't. All you do is run around under him until he shoots his deathbeam (he only does so usually if you are under him), then step aside and take the opportunity to unload your hammers on him (he moves very slowly while shooting the beam). If you do it right and are lucky, he'll practically fire it continuously. Don't get too close though - he's poisonous to the touch! He's something of a superstar, having appeared in both Spooky Castles AND Dr. Lunatic.