Tantamount Gash

When you're taking damage from a creature you can see which would reduce your hit point to 0 (but not killed you outright), you can use your reaction to deal [roll]8d8[/roll] necrotic damage towards the attacker. This damage will bypass any resistance and immunity if the target creature has any but won't have any effect against construct.

If this spell successfully reduce the target's hit point to 0, you'll instantly brought back to life (no need for death save) and healed for [roll]1d4[/roll].

At Higher Levels. When you cast this spell using a spell slot of 6th level or higher, the Healing increases by 1d4 for each slot level above 5th.