Cobra Kai

From Encyc

The Cobra Kai was a fictional karate school that taught the antagonists in the movie, The Karate Kid. The leader of the Cobra Kai was an immoral adult who encouraged the children to have "no mercy" and to pick on weaklings. During the karate match, he ordered one youngster to "sweep the leg", which was an illegal move that seriously injured another competitor.

This contrasted with the teachings of Mr. Miyagi, who encouraged self-discipline, kindness, and restraint.