Starfish
Please no sarcasm
Any spirit that wants to cause problems.
Think about it...
How many people on this forum alone have accused the Mormons of worshiping a different Jesus than the "Biblical" Jesus?
Does that really make sense to you? The good done by the Mormon Church far out-weighs the ruffled feathers of the non-LDS.
So your best answer is "The Devil made him do it"? What did Joseph gain from all this?
Money? He never had any? Power? He was hunted, mocked, persecuted, and tortured. He lost children to death due to the persecution. He gave his life. Fame? He would have prefered to live quietly with his family.