Chromatic Hydra

You conjure 2 hydra heads made of arcane energy that takes up a 5 foot cube of space within range. On subsequent turns, when you cast a spell that targets a single creature, you can make the hydra attack your target as a bonus action. Each head makes a ranged attack roll against the target. On a hit, the bolt deals 1d6 damage. The type of damage dealt is based on the damage roll. 1-acid, 2-cold, 3-fire, 4-lightning, 5-thunder, 6-your choice.