Delayed Consequences

You touch a willing creature and alter their form, changing the way they experience bodily harm over time. Any non-psychic damage they would receive is instead reduced to one, and they are immune to necrotic damage.

Once the spell ends on a creature they take all the damage prevented, except necrotic damage, at once, as necrotic damage. This damage overcomes all resistances and immunities. In addition the creature must succeed a constitution saving throw, suffering two levels of exhaustion on a failure or one on a success. You automatically fail the saving throw if you are reduced to 0 hp from the damage taken.

The spell ends early if the target creature drops to 0 hit points, or their form is altered.

At higher levels. If you cast this spell using a spell slot of 6th level or higher, the duration is concentration, up to 10 minutes. If you use a spell slot of 7th level or higher, the duration is 8 hours. If you use a spell slot of 8th level or higher, the duration is 24 hours. Using a spell slot of 6th level or higher grants a duration that doesn't require concentration.