Knockouts are ROBLOX's slang word for kill. You obtain one by killing a User. Some games contain this and others do not. For example, you would probably find this in a swordfighting game (KOs are usually the main objective), but not in a tycoon (Most tycoons people would find annoying, as it disturbs their work. There are exceptions, mostly war tycoons). Sometimes, a user kills a user after he himself has been killed. This can be the effect of hacking, or lag (especally connection lag).