I'm guessing here, but I think it was reared up as in "I want you to let go of my halter."

I too thought of the treat feeding as a real problem. They used to rent a house on our property and they liked to feed my horses stuff. We had a couple rounds of "do not feed the horses" because one of them is IR and also I didn't want the horses to learn bad manners. I also told her to  make sure and have something to wallop him with when he turns his butt to her in a threatening manner. If he has done these other things, that one is not far behind.

This animal was a mistake to get, but... well, it isn't at my house.