We used to have a paint stud at our barn who we do believe was insane...Yes I know he was a stud but it was his behavior that made us believe it. Rio was an absolutely gorgeous paint, but he wasn't originally ours. He came to as an a abused rescue. When he was in his stall he would bite at himself. Yes, many of you would say that we should have had him checked out by a vet, but we couldn't because if you went anywhere near his stall, or if he even saw a glimpse of you, he would freak out and start bucking, rearing, and kicking the walls of his stall. If you went into his stall he would full blown attack you, he would bite and strike at you.
In the pasture he would run around constantly and if you went to go get him he would try to attack, he couldn't be worked at all. Like I said before he'd attack.
So my RI bought a muzzle for him and we were finally able to brush him and get near him without feeling too worried. But we still couldn't do anything with him he was still too dangerous. He wouldn't let a vet near him so my RI sent him out to pasture and none of his babies seem to have any of his problems....of course none of his babies are at the barn.
Another story would be about the three foals of a champion mare at our barn. They were savage from the day they were born. They would attack you if you went anywhere within reach of them. You could clip them but heaven forbid you turn on a light. You couldn't catch them in the pastures. No matter how they were handled they were uncontrollable. Especially under saddle. They couldn't be stopped. They were also extremely ugly, my RI said that it was like a Mr. Potato Head, a good head on this one, a good neck on a different one, etc....But only one thing was good on them. No matter who the dad was.
"And somewhere in the northwoods darkness a creature walks upright. And the best advice you may ever get is: Don't go out at night..."