Breeun's Rail Gun

You fire a piece of ammunition at incredibly high speeds in a 30 ft. line centered on yourself. Creatures in that line must make a Dexterity saving throw. On a failed save, they take 1d6 piercing damage and 1d4 thunder damage (roll for damage once). On a successful save they take no damage. This can hit up to three creatures and if a creature succeeds on the saving throw, they do not count against the maximum. 

At higher levels. When you cast this spell using a spell slot of 2nd or higher, the damage increases by 1d6 piercing damage and 1d4 thunder damage for each spell slot level above 1st. When you cast this spell using a spell slot of 3rd of higher, the range increases by 5 ft and the number of creatures you can hit increases by one for every two spell slot levels above 1st.