Aging Touch

Make a melee spell attack against a Beast, Giant, Humanoid, or Monstrosity. On a successful hit, the target is aged and cursed. While cursed this way, it has Disadvantage on Strength, Dexterity, and Constitution ability checks and saving throws. The aging is reflected in the target's appearance: skin becomes more wrinkled and pockmarked, hair turns gray or white, posture begins to stoop. Incidentally, the curse provides Advantage on checks made to attempt a disguise. 

At the end of each of the target’s turns, the target must make a Constitution saving throw. If the target succeeds on three of these saves, it is no longer cursed, and the spell ends. If the target fails three of these saves, the target's walking speed is halved, and it is subjected to the curse for the spell’s duration.

Casting Aging Touch on a creature already cursed by the spell has a different effect. On a successful melee spell attack, the target takes 6d10 Necrotic damage, as its body succumbs to the ravages of incredibly swift decay. If this damage leaves the creature with 0 Hit Points, it instantly dies of old age (no death saving throws). The duration for subsequent castings of this spell is Instantaneous; only the initial curse lasts for 7 days.

A Remove Curse or Greater Restoration spell ends the curse, immediately negating the Disadvantage on ability checks, but not the loss of hit point (if any). The creature's appearance is gradually restored in 1d4 days. A Remove Curse spell can also be cast on the corpse of a creature that died because of Aging Touch. Otherwise, spells such as Revivify or Raise Dead fail to bring the creature back to life.

Using a Higher-Level Spell Slot. When casting this spell using a 9th-level slot, the duration is permanent. 

Adapted from Dragon Magazine #350