Paizo, https://www.d20pfsrd.com/magic-items/magic-armor/specific-magic-armor/mistmail

Mistmail

Adventuring Gear Magical +1 Chain Shirt. Very Rare (this item requires attunement) [4 Days, a strong prayer to the tempest god.]

The fine links of this +1 chain shirt form a pattern of roiling clouds. On command once per day, the wearer can transform it into thick fog that fills his space (5 ft, only the wearer) and provides concealment (disadvantage on attacks) for 3 minutes. This mist moves with the character. Effects that disperse the mist or destroy it cause the armor to reform into its solid shape on the character’s body, as does speaking the command word or entering a place where the fog-magic doesn’t function (such as underwater). If the character tries to don another suit of armor while the mistmail is in fog form, it reforms at the character’s feet.

Cost: 2,250 GP Weight: 10 lb