The Power of Taboo! Kurama's Intellect Yu yu hakusho : Season 3 Episode 69

Kaitou's devious game becomes a fight for survival as Hiei, Botan, and Kuwabara all fail prey to the twisted teen's bizarre rules. But Kurama issues a challenge...one by one the letters of the alphabet will become taboo. If any of the taboo sounds are uttered, the speaker will face a terrible penalty. Placing his own soul on the line, Kurama prepares himself to battle wits with the brilliant Kaitou.