Xephy's Constellation

A blinding arc of solar energy leaps forth from you toward a target of your choice that you can see within range. The arc then passes through from your primary target to a second, a third, and so on to a maximum of eight targets. All of which must be within 60-feet of the primary target. A target can be a creature or an object and can be targeted by the arc only once.

Taste The Rainbow. A target must make a Constitution saving throw. The Primary target takes 10d6 radiant and 10d6 fire damage on a failed save or half as much on a successful one. Each subsequent target takes one dice less of each damage type. For example, the second target only takes 9d6 of radiant and fire damage on a failed save, the fourth target would only take 7d6 of radiant and fire damage on a failed save.

At Higher Levels. When you cast this spell using a spell slot of 8th level or higher, you increase the damage die on the primary and subsequent targets by 2d6 of each damage type for each slot you use above 7th.