Player's Handbook

Ray of Enfeeblement

2-level Necromancy

A black beam of enervating energy springs from your finger toward a creature within range. Make a ranged spell attack against the target. On a hit, the target deals only half damage with weapon attacks that use Strength until the spell ends.
At the end of each of the target's turns, it can make a Constitution saving throw against the spell. On a success, the spell ends.