You can draw upon an inner nexus of necromantic power. You have a pool of Charnel Touch points equal to 5 x your Necromancer level that replenishes when you finish a Long Rest.
As a Magic action, you can channel this negative energy through your touch. Choose a number of Charnel Touch points to expend, up to a maximum of 5 x your Proficiency Bonus, and make a melee spell attack against one creature within reach. On a hit, the target takes Necrotic damage equal to the number of points expended. This damage is doubled without expending additional points if the attack roll scores a Critical Hit. If the spell attack misses, the Charnel Touch points aren't expended.