batsu game; forfeit; punishment game
A penalty or silly task imposed on the loser of a game, often in variety shows or among friends.
じゃんけんで負けたら罰ゲームとして変顔をしなければならない。
If you lose at rock-paper-scissors, you have to make a funny face as a penalty.
The punishment games on TV are always funny.
Compound of 罰 (batsu, 'punishment') and ゲーム (gēmu, 'game'). The exact origin is uncertain, but it likely emerged from Japanese variety shows and party games.