Dual Element Blast

You raise your arcane focus, whether that be your staff, wand, hand, or something else, and either side/end lets out a 5ft wide 20ft long blast of elemental energy. The caster can orient this in any way, but the blasts must go in completely opposite directions (east/west, up/down, etc). On the casting of this spell, the caster must choose or roll for 2 different damage types from the table below, and decide which type corresponds to which end of the blast. Every creature caught in the blast of this spell must make a Dexterity saving throw against your spell save DC or take 4d8 of the type of damage that end of blast is doing, or half as much on a successful one.

When cast at higher levels, each end of the blast does 1d8 more damage per additional level of spell cast.