What to do about my retarded, getting more aggressive by the day, horse?

I'm mad at my retarded horse right now. First he wouldn't let me catch him, unusual. Then after he drug me a few feet & I caught him, I tied him up. I was gonna leave him there for a little because he was almost running me over where he wouldn't have to be tied up. What's he do? He rears, flips out, breaks one of my lead ropes. So I spend another 20 minutes catching him, get drug by him again, drag him to the hitching post again, use a invincible lead rope, he flips out & rears & kicks & jumps backward & & leans all his weight onto the hitching post, now that it's invincible too, my parents where "stay back, stay back, he's gonna hurt you" since he was lunging at the post every couple seconds. I just wanted to unhook him from the lead rope before he killed his stupid self. What'd they do? They went over there to try & do it! My grandma almost get's him on her because he decided to rear & lunge at the hitching post while she was over there. I finally got it off of him. What the hell do I do about him? Do I just break down & get him another horse? He's been getting worse & worse & worse as time goes on & Penny isn't coming back.