Borrowed Vitality

You point at a creature in range and hinder their vitality, using it for your own gain. The creature makes a Constitution saving throw. On a fail, it takes 3d8 necrotic damage, and you gain half the damage dealt in temporary hit points. Additionally, for the duration, the creature cannot regain hit points by any means, and when it would regain hit points, you regain them instead. On a successful save, the creature takes half damage and suffers no additional effect, including you gaining the temporary hit points.

At higher levels: When you cast this spell with a spell slot of 5th level or higher, the damage increases by 1d8 for every spell slot above 4th.