Aldra's Chain of Explosions

A bright streak flashes from your pointing finger to a creature of your choice within range which blossoms into a series of blazing explosions. That creature must make a dexterity saving throw, combusting in fiery explosion that expands in a 20-foot radius and taking 10d8 points of fire damage on a failed save.  Creatures within an explosion caused by this spell must also make a dexterity saving throw taking the same damage and combusting in a new 20-foot radius explosion. A creature that succeeds their save takes half damage and does not combust. A creature can only be affected by an explosion once per casting of this spell.

At Higher Levels: When you cast this spell using a spell slot of 7th level or higher, the damage increases by 1d8 for each slot level above 6th.