Twilight's Mantle

The cloak that's the material component becomes infused with wisps of shadow material from the Shadowfell, causing the cloak to move subtly as if with a will of its own. You resist cold damage and become acclimated to cold environments for the duration. Whenever a creature touches you or hits you with a melee attack within 5ft of you, the creature takes cold damage equal to your SAM.

Also, you make attacks with advantage against incorporeal creatures and bypass the resistances of such creatures. The spell ends early if you're in bright light.