I don't know of this as been posted already, if it has then sorry.

This glitch happen in practice mode on my Xbox, not sure about PS2 or GC, but try it and see. If you do Scorpion's front thrust kick (up+B)in his Hapkido style your opponent flies into the air. As soon as you do that move, throw his spear. When Scorpion throws his spear he takes a step forward. He'll step forward and end up on the other side of his opponent when his spear hits. It only last a second so pause the game before he pulls them in. You'll see that the spear is stuck in their back.

Make sure your as close as you can get, do it fast and it dosen't matter who you put as Scorpion's opponent. It mite not happen the frist time, but it will happen.