[Winter] Item - Blizzard Coat

Blizzard Coat
Wondrous item, rare (requires attunement)

A piece of Maelstrad itself, this cloak is granted to individuals worthy of upholding the ideals of the primordial tempest.

Fade into Snow. While wearing this coat, you swiftly camouflage into icy surroundings. If you do not spend any movement on your turn while you are in a lightly obscured environment caused by snow, hail, or other wintery weather, you automatically attempt to Hide in the environment at the end of your turn. 

Storm Form. While wearing this coat, you can use a bonus action to briefly transform into a storm. Until the end of your turn, you do not provoke attacks of opportunity and you can move through gaps as small as 1 inch or creatures as if they were difficult terrain. If you move through a creature, you can expend up to 3 hit dice and force the creature to make a DC 15 Constitution saving throw. On a failed save, the target takes cold damage equal to one roll of each expended hit die, or half as much damage on a successful save. A creature can only take this damage once on your turn. Once used, this property cannot be used again until you finish a short or long rest.