Death's Touch (5e Spell)
From D&D Wiki
|Casting time:||1 Action|
|Components:||Diamond Dust worth 500gp|
You touch one enemy creature within 5ft of you. You speak an ancient ritual in your mother dialect and offer the components to your deity. The target creature must succeed on a DC Constitution Saving Throw (using your spellcasting ability as the DC to beat), if the creature fails the saving throw, it must take 10d8 necrotic damage and have that amount added to your hit points as temporary hit points, if the creature succeeds the saving throw, it must take half of the 10d8 damage rolled and it's damage is not added to you for temporary hit points.
At Higher Levels. When you cast this spell using a spell slot of level 7 or higher, increase damage dice by 1d8 for each spell level.