You might second guess calling this weapon a flail when comparing its bulk to any other. Its spherical head is attached to a reinforced ash pole about 4 feet long. The head is made out of a material you have never felt before, it is pitch black and gives slightly to the touch. When you hit things with it it rebounds slightly as if bouncing despite its solid impact. It weighs 8 pounds, has the properties Heavy, and Two-handed, and deals 1d12 bludgeoning damage.
As an action you can make an attack with reach. If this attack is successful you may use the rebound of the strike to make another attack with reach against a different target within 5 feet of the original target as a bonus action.