They never reveal who the real monster was. But my personal head canon is that it was Scrappy all along, messing with the gang (at their request) to make the documentary look good. I firmly believe they faked the whole thing.
Would you please watch your language while on this wiki? I want to keep discussions clean of words like you used. You can complain without the use of expletives. I will remove that part, and maybe you can replace it with something less offensive. Hope you can appreciate this. Thank-you.