The Raven's Judgement

You point at a creature you can see within range creature to unleash the Raven Queen's Judgement on it. The target makes a Constitution saving throw. On a failed save, it takes 7d8+30 Necrotic damage, and its Hit Point maximum is reduced by an amount equal to the Necrotic damage it took. On a successful save, it takes half as much damage only. This spell can’t reduce a target’s Hit Point maximum below 1.

If the spell reduces a creature to 0 hit points, its corpse is marked by a black feather that prevents it from being raised as undead by any means, unless by a Wish spell.