Caligos' Black Serpent

Flame-like shadows undulate along the ground creating a 60-foot-long, 5-foot-wide path within range. The area of the spell consists of up to twelve 5-foot Cubes, which you arrange as you like along solid ground or up walls. Each Cube must be contiguous with at least one other Cube, and together the Cubes must make a singular shape. If there is no room for the path of Cubes to continue, the path ends. Each creature in the area makes a Constitution saving throw, taking 6d6 Necrotic damage on a failed save or half as much damage on a successful one.

At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, the damage increases by 1d6 for each slot level above 3rd.