Bascially it is a 8th level necromancy spell and whose casting time are 1 action. The components of this spell is a bit of sponge.
Abi-Dalzim’s Horrid Wilting
Casting Time: 1 action
Range: 150 feet
Components: V, S, M (a bit of sponge)
Spell List: Sorcerer, Warlock and Wizard
Source: Xanathar’s Guide to Everything
You draw the moisture from every creature in a 30-foot cube centered on a point you choose within range.
Each creature in that area must make a Constitution saving throw. Constructs and undead aren’t affected, and plants and water elementals make this saving throw with disadvantage.
A creature takes 12d8 necrotic damage on a failed save, or half as much damage on a successful one.