Zatch Bell!: Season 1, Episode 50

1 - 50: The sixth spell

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!