Power Word Kill

9th-level Enchantment
Casting Time: 1 action
Range: 60 feet
Components: V
Duration: Instantaneous

You utter a word of power that can compel one creature you can see within range to die instantly. If the creature you choose has 100 hit points or fewer, it dies. Otherwise, it takes 12d12 psychic damage.

At Higher Levels. When you cast this spell using a spell slot of 10th level or higher, you can target one additional creature for each slot level above 9th.

Source: PHB 266, SRD

Changelog

Altered effect so it now damages creatures not instantly killed by the spell.
Added upcasting option.
Altered damage type and number, removed somatic component.