The PA Missile is a build based off a video by JimBenDoto (Couldn't find the original), where you get 3+ battle furies and then throw a dagger at some creeps near a hero and hope it crits, if it does you are doing around 160% cleave dealing more damage to the cleaved enemies than your original target and when you are dealing 1400 crit damage you do about 2200 damage with cleave.