Bardoq The Magnificent's Super Slick Trick (Tm)

You create a 5ft by 10ft slick of oil at a point or on a surface within range. You may choose the type of oil when casting the spell. Any creature attempting to move through the oil or starting, or ending its turn in the oil must make a Dexterity saving throw. On a failed save, the creature falls prone. Creatures using the Dash action or moving at a fast pace when attempting to cross the slick make this roll at Disadvantage. This spell scales with level, and increases in area at the 5th, 11th, and 17th levels, gaining an additional 5ftx5ft to its total area. You can choose the shape/configuration of the slick when you summon it. Starting at 11th level, you can instead choose to summon enough oil to fill a 5ftx5ft cube within range, no more than 10ft above the ground.