Replacement Series
8-level Necromancy
You shrivel and decay every living thing within a 30-foot cube you can see within range, sucking the life away until the targets crumble to dust. Each creature in the area must make a Constitution saving throw. On a failure, the target takes 12d8 necrotic damage, has its speed halved and has disadvantage on all of its attack rolls and ability checks until the end of its next turn. On a success, it takes half as much damage and suffers no other effects.
Constructs and undead automatically succeed on this saving throw, while plants have disadvantage. Anything reduced to 0 hit points while under the spell's effect crumbles to dust.