Rod, very rare (requires attunement)
This elegant rod is 1 inch thick, 3 feet long, and made of lustrous silver. It has 4 charges and regains all expended charges daily at dawn.
While holding this rod, you can use an action to expend 1 charge to transform it into any weapon, armor, or piece of adventuring gear found in chapter 5 of the Player’s Handbook, so long as you’ve seen the item before.
The new object is made entirely of silver, which might affect its usefulness; for example, a silver rope would be hard and unyielding. If formed into armor, it provides the same level of protection as that armor usually provides. If formed into a weapon, it inflicts the same damage as that weapon usually does. Attacks made with the weapon are magical and silvered.
The rod retains this new form until you use a charge to change it back into a rod again.
-Mordenkainens Tome of Marvelous Magic II (modified)