Oil of Etherealness
Potion,
Rare
(cost 3500 gp)
Crafting Components
Stable ectoplasm, ghost trapped in a bottle
This misty white solution has turned to vapor in its vial, becoming liquid again when shaken. You can spend 10 minutes applying the ephemeral substance to a Medium or smaller creature, as well as its gear. One additional vial is required for each size category above Medium. A creature covered in the oil becomes ethereal (as the etherealness spell) for 1 hour.
Source