Chromatic Aegis

The caster breathes upon a diamond, refracting their magical energy into five orbs that orbit one foot away from the caster. As a bonus action, the caster may send one of the orbs (their choice) to any target within 60 feet that the caster can see. The caster makes a ranged spell attack roll. While concentrating on the spell, and if any orbs remain, a successful melee attack against the caster, and made within 5 feet of the caster, causes one of the remaining orbs (determined randomly) to hit the attacker without requiring a roll. 

The orbs' elemental energy are: acid, cold, fire, lightning, and poison. Each orb deals 4d6 damage of its type to a target.