Sphere of Holding

This round metal sphere is precisely 6 inches in diameter. As an action, you can speak the sphere's command word and make a ranged attack roll with it, out to a range of 60 feet. As it's thrown, the sphere expands, becoming Large, and it deals 3d8 bludgeoning damage on a hit. Each creature in a line 30 feet long and 10 feet wide directly behind the target must succeed on a DC 15 Dexterity save or take the same damage. On a miss, the sphere fails to expand and lands harmlessly within 5 feet of the target.

As an action, you can speak the sphere's command word and cause it to shrink back to its usual size. The sphere weighs the same amount in both forms.