Darwin’s Horrid Acid Nightmare

You create a nightmarish illusion of acid seeping from the pores of every creature in a 30-foot cube centered on a point you choose within range. Each creature in that area must make an Intelligence saving throw. Constructs and undead aren’t affected, and dragons and humanoids make this saving throw with disadvantage. A creature takes 10d8 necrotic damage on a failed save, or half as much damage on a successful one.