Bardo

3rd-level necromancy (liminal)
Casting time: 1 reaction, which you take when you see a creature within 30 feet of you die
Range: 30 feet
Target:
Components: V, S, M (a pinch of dirt from a graveyard)
Duration: Instantaneous
Classes: Cleric, Paladin, Sorcerer, Wizard
Subclasses:

You capture some of the fading life essence of the triggering creature, drawing on the energy of the tenuous moment between life and death. You can then use this essence to immediately harm or help a different creature you can see within range. If you choose to harm, the target must make a Wisdom saving throw. The target takes psychic damage equal to 6d8 + your spellcasting ability modifier on a failed save, or half as much damage on a successful one. If you choose to help, the target regains hit points equal to 3d8 + your spellcasting ability modifier. This spell can’t be triggered by the death of a construct or an undead creature, and it can’t restore hit points to constructs or undead.