Oil of Slipperiness

You can spend 10 minutes applying this thick black oil 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 gains the effect of a __freedom of movement_ spell for 2 hours. Alternatively, you can use an action to pour the oil on the ground next to you, making a 10-foot square slippery (as the _grease_ spell) for 8 hours.