Wait, I'm a bit confused, does "Impossible to remove" mean that you can't heal the wound? That's rather harsh.
Anyway!
You could choke someone to death with it, but killing someone is hardly the worst you could do to someone.
Pinning someone to a wall, now they are your prisoner forever! Or at least until someone breaks down the wall.
Wait, scratch that, pin someone to somebody else.
When I first clicked on this thread, I though it would be the arrow version of the Immovable Rod. Hit someone, and they are stuck in place until they manage to rip themselves free with a significant HP cost.