Snow Boulder

A ball of snow forms 5 feet away from you and rolls in the direction you point at a speed of 30 feet, growing larger as it moves. To roll the boulder into a creature, you must make a successful ranged spell attack. If the boulder hits, the creature must make a successful Dexterity saving throw or be knocked prone and take the damage indicated below. Hitting a creature doesn’t stop the snow boulder’s movement or impede its growth, as long as you continue to maintain concentration on the effect. When the spell ends, the boulder stops moving.