hey guys i need this question answerd

recently i have been playing fireteam and i have been seeing people using a hack i have never seen before they fly up in the sky nd shoot down unlim rockets i was just wondering if anyone knows wat it is thanks

iT'S a different site that I can not mention, but the hacks is called knife hack (I think), where they use a drop down menu to select various weapons to use, they also use aimbots and OPK's!