This is a severe sickness that makes the victim get very angry over losing in a game. This applies mainly to gamers and a thing scientists call Skill Exposure. The Skill Exposure, or SE means that the victim will get mad because they will be exposed to users with far more skill than themselves. This is common and will go away in a week to a month, sometimes a year of its that bad.
Dude, John is acting like he has Hudioloftiopcuitiostuiriounominebiounherbgerynabverherglekarbluemarkleusinoscopitius right now.