You call upon the power of earth to create a stable surface on a rock or boulder within range. The rock becomes smooth and polished, allowing you to ride it like a surfboard.   When you cast the spell—and as a bonus action on each of your turns thereafter—you can direct the rock to move up to 30 feet in any direction. You must be on the rock to control it, and it can carry up to your weight plus an additional 500 pounds. If you move the rock off of solid ground, it will drift through the air until it reaches solid ground again, at which point it will come to a stop.   While you are riding the rock, opportunity attacks are made against you with disadvantage, you have advantage on Dexterity (Acrobatics) checks, and you reduce any fall damage you take by five times your level.