Netherclasm

8th-level necromancy
Casting time: 1 action
Range:Self (60-foot line)
Target: Creatures within a 60-foot line, 30-feet wide
Components: V, S, M (a pound of rancid meat)
Duration: 1 round
Classes: Warlock
Subclasses:

A flood of ebon netherplasm extends from you along the ground in a 60-foot line that is 30 feet wide. Creatures in the area have their speed halved and have their vision reduced to 10 feet. At the start of your next turn, the area erupts in a blast of netherplasm that is 60 feet high. Creatures in the area when it erupts must attempt a Constitution saving throw, taking 12d10 necrotic damage on a failure, or half as much on a success.