Superknife

Superknife can either be a hack or a mod that greatly increases the speed at which you swing your melee weapon. It can apply to one specific melee weapon or all of them. This hack is rather difficult to detect, as it's client-sided and not always visible. Some sure-fire ways of detecting this are listening to how fast someone swings their knife or playing in Quarantine Mode and seeing a large drop ( around 100 or more) in HP after only one hit.