Metabot's Manual of Magical Maneuvers

Blood Barrier

2-level Necromancy

You sacrifice some of your life essence and evoke a shimmering sanguine shield. As a part of the casting of this spell, your maximum hit points and current hit points are both reduced by 3d6, lasting until you finish a long rest. You create a magical ward made from your life essence, lasting for the spells duration. It has hit points equal to the amount your maximum hit points were reduced, and whenever you take damage, the ward takes the damage instead. If this damage reduces the ward to 0 hit points, you take any remaining damage.
Additionally, a tide of crimson blood streaks outwards, transfixing creatures in your proximity. Creatures that ends its turn within 5 feet of you must succeed on a Dexterity saving throw or take 3d6 necrotic damage.
At higher levels: When you cast this spell using a spell slot of 3rd level or higher, add an additional 1d6 when reducing your current and maximum hit points and when a creature takes damage from this spell for each slot level above 2nd.