Today, I pulled Hoover and stalled him when I was taking lessons. I think it made him angry with me, he does get that way if he sees me on other horses.
When I got him out later to grass, I was fake mounting (jumping by his side and putting pressure with my hands on his back), just fooling around. It's something I usually can do with him out in the field without any tack on and he just stands there. Today he came around on me, threatening to bite. When he continued after discipline, I got one of my instructors daughters to hold his head while we worked him a little with it. Once I was on his back, which I've barebacked before and he's been an angel, he started circling and violently switching his tail like I was hurting him. He had us both convinced his back hurt, so he got out of having to work! He's never pulled the injury game with me before, what a booger!