Aneurysm

You touch one unconscious creature within reach, forcing them to make a CON save. On a success, the creature suffers one level of exhaustion. On a failure, if the creature has less than 50 hit points, they die immediately as an aneurysm causes instant brain death. Otherwise, the creature suffers three levels of exhaustion. Conscious creatures, undead, and constructs are immune to this spell. 

The blood needed for this spell takes a toll on you, dealing 5d8 necrotic damage to yourself.