I've picked up the harpoon firearm a few times now, and I can't figure out what it's for.
- Shooting an enemy rider with it doesn't appear to do much but briefly stun them as with a melee attack, and with no discernible damage.
- Shooting the ground or an object tethers me to it with a wire, but this doesn't have any effect that I can figure out either. Once I drive past my harpoon the wire just extends out behind me, as seen (sort of) in the image below.
What do I use the harpoon for?