Cage of Mirrors

You surround a creature you can see within range with 5 rotating mirrors that ward the creature against attacks. Until the spell ends, any creature who targets the warded creature with an attack or a harmful spell must first make an Intelligence saving throw. On a failed save, they must roll a d6. If the creature rolls above the current number of mirrors, the attack continues with no effect. If the creature rolls equal to or less than the current number of mirrors, the attack strikes a mirror and the creature suffers 4d6 piercing damage as the mirror shatters and shards of glass embed themselves into their body. This spell ends once all the mirrors have been shattered or you lose concentration. This spell doesn't protect the warded creature from area effects, such as the explosion of a fireball.

At Higher Levels: When you cast this spell using a spell slot of 4th level or higher, the damage increases by 1d6 for each slot level above 3rd.