The title should warn you this is clearly NSFW;
That video is among the most fucked up things I have ever seen. It's not some grosse pseudo-sexual feces play, those are just sick and kindof funny. This is a horrible act of cruelty from one guy to a helpless animal. I know animals have to be put down when it's just worse to leave them to dying in pain; example starving dogs in Iraq getting shot/thrown off of cliffs... but this is just too much.
The people who videotaped it instead of running to help should be ashamed and even punished as the attacker.
