For this to work you have to be in two player. One person has to get a sniper rifle or a covenent. Have the other person get a weapon that has a good melee attack. Have the guy who has the sniper rifle or a covenent set up in a location were other aliens will have a hard time getting them. Have the person who has the gun go after the hunter (so he doesnt shoot the other person). While the your parter is in a melee attack with the hunter shoot it in the head or waist. You will kill it after three or four shots.