Zatch Bell!

Season 1, Episode 50

Episode Title: The Sixth Spell

Air Date: 2004-03-28

Overview:

Kiyo and Zatch are accosted by Dr. Riddles and Kido, who use odd tactics to try to defeat our heroes. After a number of confusing riddles and puzzles, the two human/mamodo teams finally battle it out. But it seems that Dr. Riddles has learned the ins and outs of the spell book!