Exhaustion Bolt

You fire a bolt of horrifically negative energy. You make a ranged spell attack to see if this bolt hits. On a successful hit, the creature suffers one level of exhaustion. This exhaustion acts like normal exhaustion would, meaning one level of it goes away upon taking a long rest. This spell can be cast several times, resulting in several levels of exhaustion. If you critically hit on the ranged spell attack, this afflicts two levels of exhaustion instead of one.