a sling made out of a squirrel, which you twirl around and throw a metal acorn or something at your target. It could come with the achievment 'heartstopper' or 'heartbreaker'. It wouldn't have any penetration, it'd work by using percussive force or something(idk I'm not too smart).
and/or a slingshot for hunting small game up close, it'd weigh probably as much as ammo