击倒（knockout），也称为击倒游戏（knockout game）、“K.O.王”（knockout king）、“轰炸”（bombing）、“打北极熊”（polar-bearing、polar-bear hunting），是2012年至2013年发现的主要在美国黑人间流行的一种暴力袭击游戏 。游戏参与者会随机选定行人或其他陌生人为目标，趁其不注意时冲到受害者身边施以重拳，力求一拳将受害者击昏倒地（一击K.O.）。有的参与者会将过程拍摄下来上传至互联网。这种游戏已经导致多人重伤甚至死亡。某些发生击倒案例的市镇警方碍于逆向种族主义而声称所谓击倒游戏是都市传说，是将某些零星袭击事件串联的结果，是一种道德恐慌。另外的看法则认为击倒游戏中有种族动机，是族群之间的仇恨犯罪。

The "knockout game" is one of the many names given by the American news media to assaults in which one or more assailants attempt to "knock out" an unsuspecting victim. This is often done with a single sucker punch for the amusement of the attackers and their accomplices. Other names given to assaults of this type include "knockout", "knockout king", "point 'em out, knock 'em out", "bomb", and "polar-bearing" or "polar-bear hunting" (allegedly called such when the victim is white).