You raise one Medium or Small humanoid corpse as a ghoul under your control. Any class levels or abilities the creature had in life are gone, replaced by the standard ghoul stat block.
Using a Higher-Level Spell Slot. When you cast this spell using a 3rd-level spell slot, it can be used on the corpse of a Large humanoid to create a Large ghoul. When you cast this spell using a spell slot of 4th level or higher, this spell creates a ghast, but the material component changes to an onyx gemstone worth at least 200 gp.