Kayn syndrome
Used to describe a phenomenon where Kayn players, in the game league of legends, are incredibly bad and awfully terrible in your team but are godlike entities when played by the other team. This includes: Going AFK, saying slurs, tilting, feeding (giving kills to the other team).
Bro he went 0/10 and then called my mother a whore before leaving the game. This is such a Kayn syndrome.