Cloak of the Sanguine

You sacrifice blood to envelope yourself in a layer of magical blood that covers your armor in an ever-moving layer of blood. The armor has hit points equal to twice as many hit points you sacrificed. As a reaction to getting hit, you can roll a d6 and add it to your AC, if that causes the attack to miss, spikes of blood erupt from the armor and deal 3d8 necrotic damage. When the armor's hit points reaches 0 the spell ends.

At Higher Levels. At Higher Levels: When you cast this spell at 4th level or higher, the blood cost increases by 1d10, the damage also increases by 1d8 for each slot level above 4th.