As part of casting this spell, you must expend six hit dice or the spell automatically fails. If you do, you cast this spell, a rose-colored mist billows up from the spot you indicate within range, obscuring sight and draining blood from living creatures. The cloud spreads around corners. It lasts for the duration or until strong wind disperses it, ending the spell. Its area is heavily obscured.   This cloud leeches the blood or similar fluid from creatures in the area. It doesn’t affect undead or constructs. Any creature in the cloud when it’s created or at the start of your turn takes necrotic damage, equal to a roll of the hit dice expended to cast this spell, and gains one level of exhaustion; a successful Constitution saving throw halves the damage and prevents gaining exhaustion. At the start of each of your turns, you gain temporary hit points, equal to the amount of other living creatures currently inside the cloud.