A 4 way demo into a football field supposed to be from 2500 ft but a cloud deck came in and the highest we could get was 800 ft. I was spotter and looking down thought no way we're going to do this but some impulse made me, like a dumbass, exit the aircraft. I landed with a one minute smoke canister that burned for 40 seconds after I was on the ground. Even the wuffos at the event were shocked and questioned the altitude. Amazingly, the other three guys jumped also and when they landed they were all highly pissed at me because we had jumped from such a low altitude. Everyone on the load knew the altitude and nobody forced anyone to jump. They didn't refuse the money paid them for the demo, though