This so called hammer is a nearly perfect sphere, 1 foot across, made out of red granite. It has a thick brass band around it that is heavily dented and a single heavy brass chain attached to the band at each end, forming a loop. This small boulder weighs a full 80 pounds.
Once per short rest as an action you can begin swinging the hammer around you, building up speed until it is moving fast enough and you are able to let go. When you let go it begins orbiting you of its own accord. While the hammer is orbiting you it maintains a distance of 5 feet and moves with you. Any creature that ends their turn within 5 feet of you must make a Dexterity saving throw equal to 8 + your proficiency + your Strength modifier. On a failure the creature takes 1d10 + your Strength modifier bludgeoning damage.
As an action while the hammer is orbiting you you can manipulate its speed and trajectory to make an attack against all creatures that are 5 feet away, or all creatures that are 10 feet away. Make a single melee attack roll with proficiency against all affected creatures AC. On a successful hit you deal 3d10 + your Strength modifier Bludgeoning damage. On a critical failure, or after 1 hour, the hammer falls from its orbit.