Halaster's Blackcloak (5e Spell)
From D&D Wiki
|Casting time:||1 action|
|Components:||V, S, M (a cloak or similar garb)|
As part of the casting of this spell, you don a cloak or similar garb and speak the name of a spell. Until the spell ends, your base AC becomes 14 + your Dexterity modifier, and you are immune to an enchantment, evocation, or necromancy spell of your choice. This spell is chosen when you cast this spell and the chosen spell must be of the level this spell is cast or lower. The spell ends if you don armor or if you dismiss the spell as an action.