Eldritch Beam

A line of pure energy forming a 60 feet long and 5 feet wide beam pierces thru each target with ramping force. Each creature in the line must make a Dexterity saving throw. Each creature takes 3d10 force dmg on a failed save and half on a successful one. For every creature in the line after the first, the damage is increased by 1d10.

(If 3 creatures are in the line of the spell, the spell now does 5d10 damage) 

When you cast this spell using a spell slot of 4th level or higher, the damage increases by 1d10 for each slot above 3rd.