On the episode where Yugi and Joey are dueling the big five, five monters with different attributes must be sacrificed to summon the five-headed dragon. However, two of the five monsters share the same attribute. Deep Sea Warrior and Nightmare Penguin are water attributes. Judge Man is Earth, Robotic Knight is fire, and Jinzo is dark. That's five monsters, but only four attributes. Somebody made a boo boo.