Comet Tail

A halo of freezing vapor surrounds and energizes you. Your walking speed increases by 10 feet. When you move at least 20 feet in a straight line and end your movement within 5 feet of a creature, you can use your bonus action to force them to make a Dexterity saving throw. On a failure, the creature takes 4d6 cold damage, or half as much on a success.

At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, the damage you deal is increased by 1d6 for each spell slot level above 3rd.