Chromatic Beam

You shoot a glowing beam of energy at a creature or object you can see within range. You choose for the kind of beam between acid, cold, fire, lightning, poison or thunder damage. Make a ranged spell attack against the target. On a hit, the target takes 1d6 damage damage of the chosen type. Depending on the choosen type of damage an object hit by this spell can be effected in a way befitting that damage type as long as it isn’t being worn or carried. 

 When you reach 5th level you get to shoot another beam of any type or a bigger beam that deals 2d6 damage of any kind . You gain the same upgread with reaching 11th level and 17th level.
(11th : 3 Beams or one 3d6 Beam
 17th : 4 Beams or one 4d6 Beam)

~Alternative Rule~ : If you want you can decid to make the damage type random by rolling 1d6 and take the type according to this list:
 acid ~1
Cold ~ 2
fire ~ 3
lightning ~ 4
poison ~ 5
thunder ~ 6