Ulnae's Lighting Armor

Touch a willing creature who isn't wearing armor. The target’s base AC becomes 13 + your Intelligence modifier. The spell ends if the target dons armor or if you dismiss the spell as an action.

Lightning Defense.  Whenever a creature comes into contact with the lightning armour, the creature must make a Constitution saving throw against your save DC or become paralyzed for one round. It will also receive 2d8 lightning damage on a failed save and half on a succesful one.

At Higher Levels. If the user of the spell casts the spell using a 5th level or higher slot the duration becomes 8 hours.