Encircling Tombs

You send streams of black fog flying towards up to 4 creatures within 60 feet. It lifts them up as the ground opens up beneath them, and then it slams them down into their graves as they close overtop of them. Each creature you target must make a Strength saving throw. A target takes 3d8 bludgeoning damage on a failed save, or half as much damage on a successful one. If they fail their Strength saving throw, then they are Restrained. Each round they may reroll their Strength saving throw to break free, and each round they spend Restrained they take 2d6 necrotic damage.

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