Was flying in a zone marked 250ft doing a 180 shot at about 150ft. Heard a noise behind me and this helicopter came out of nowhere and he was hauling ( Mod Removed Language) Couldn't judge its exact height but I KNOW it was not 250ft up because I had the drone up at 240 about 5 mins before and from my view he was lower. Had to nose dive the drone to be sure he didn't hit it. Anyone else ever run into this type of situation?