Patholase The Legendary Dragon Tamer

Effect:This card cannot be Normal Summoned or Set. This card can only be Special Summoned by Tributing 2 Dragon-Type monsters on your Opponent side of the Field. When this card destroys an opponent's Dragon-Type monster by battle and sends it to the Graveyard, you can Special Summon that monster to your side of the field in face-up Defense Position during the End Phase.

really good anti-dragon card (opponent has red-eyes darkness, and blue eyes on the field. tribute them to summon this. watch them rage ^_^).
I could see a deck being created around summoning this to troll your opponent.

DNA Surgery, enough said