5th-level Spell: Killing Curse

Whispering (Necromancy)

You curse a target to die. Its current and maximum hit points are reduced by 3d10 + 10. If this causes the creature to have 0 hit points, it dies.
For the duration, the target cannot regain hit points except from a spell of a higher level than this one, and any death saving throw it rolls is automatically considered a 1.
At the start of each of the target's turns, it makes a Charisma saving throw. On a failure, its current and maximum hit points are reduced by 1d10 + 10. On a success, the spell ends. A creature’s maximum hit points are restored when it finishes a long rest.
Source: KCC

• Casting Time: 1 action
• Range: 60 feet
• Components: V, S, M (something from the target creature—such as blood, hair, or scales—which the spell consumes)
• Duration: Concentration, up to 1 minute
• Ritual: No