Apologies for the video quality here, this was a really "in the moment" type thing, and the only thing I had at the ready to record in the room was a Camcorder. If Camcorder quality bothers you, I am sorry.
I know I said I wouldn't be uploading videos for a while, but this practically begged me to upload it. This is actually one of the first Red Dead Redemption glitches I have seen XD
Me and my friend Overlordof4 were playing Red Dead Redemption in the Undead Nightmare pack, and I was showing him the Unicorn and just for fun I shot it, and than this happened.
If you shoot the Unicorn in the head, it will fall over, but once it bleeds out, the ragdoll will start going nuts and flying all over the place.
Note: I am aware that others have probably uploaded info on this glitch long before me, but me and my friend had to record it because it was so random.