Arm of grapple hooking

This prosthetic arm can shoot a grapple hook up to 250ft, then you can wind it in and pulled to the target, when you reach the target you must make a saving throw (14 dex) to land, on a failed save you must take 1d10 bludgeoning damage. If you shoot an enemy with this hook they have to make a saving throw (16 dex) on a passed saving throw the grapple hook will miss them, on a failed saving throw the enemy take 1d10 damage and be pulled to you. (this only count for enemies under 30ft tall) If you grapple on to a moving thing then you have a disadvantage on the saving throw.