Draining Weapon

A weapon you touch becomes a magic weapon, it becomes hungry for blood and will start draining blood from creatures you hit with it.
For the duration, any attacks you make on a target with the imbued weapon will drain the target's blood, the weapon has a +1 bonus to attack rolls and deals an extra 1d6 damage.
If the same target is repeatedly drained of blood, it will become increasingly drained.

For every 10% of the target's max hp that is drained by the extra damage from this spell,  the target must make a constitution saving throw dc 10 or take 1 point of exhaustion.