A faint, reddish miasma envelops a creature that you can see. Whenever that creature would cast a spell by using one of its spell slots, it must succeed on a Wisdom saving throw against your spell save DC or lose one spell slot of the same level as the spell it is attempting to cast. If it then does not have enough spell slots to cast the spell it was trying to cast, the casting is wasted.

Whenever a spell slot is lost this way, the lost magical energy is converted to harmless red light: the creature emits dim light for a number of feet equal to five times the slot's level until the start of its next turn.

If cast at 5:th level or higher, the creature has disadvantage on the saving throws for this spell.