Molten Gold of the Alchemistwondrous, rare (requires attunement by a creature proficient with alchemists supplies)

This small glass sphere the size of a fist is astoundingly heavy, and appears to be mostly full of a thick golden liquid. It weighs 10 pounds and has no visible opening or markings on it.

As an action or bonus action while touching this item you can change the weight of any non-magical object you can touch. When you make an object lighter the sphere gains an equal amount of weight, up to a total of 400 pounds. When you make an object heavier the sphere loses an equal amount of weight, but the object can only gain as much weight as the sphere has to lose.
You can affect up to 5 objects at a time like this, and the effects last for up to 1 hour, or until you dismiss them.