Viper vs Fake Viper (Mamushi VS Nise Mamushi [マムシVSニセマムシ]) is the 81st episode of the original Prince of Tennis. It originally aired on the 14th May 2003.
Kaido continues to struggle against Wakato's technique, until he notices the key to Wakato's play style.
Kaidoh is about to have a match with Shonan's Wakato, whom in an episode before, dissed Kaidoh's snake.
Wakato's special skill is the ability to copy the techniques of famous tennis players, such as Hewitt, Sampras, McEnroe, etc. He has the ability to change from one style to another and each style is an exact copy of a different professional tennis player, however, Kaidoh successfully counters each attack.
But then, Wakato changes into "Kaidoh" and adopts the exact playing style as Kaidoh, so in the end, it is as if Kaidoh is playing himself.