Spellburn

9th-level Abjuration

Casting Time: 1 action
Range: 60 feet
Components: V, S, M (the gemstone tooth of a demilich worth at least 1000gp)
Duration: Instantaneous

Similar to the spell revoke, this magic targets spellcasters at the core of their magical ability. When you cast this spelL choose a target you can see within range, which must then make a saving throw with its spellcasting ability score. If the creature does not have a spellcasting ability score specified, it makes a Constitution saving throw instead If the target does not have spell slots, you take 18d6 + 40 necrotic damage.

On a failure, the creature is subjected to a burning magic malaise. Each time the creature casts a spell using a slot of 1st level or higher, they must repeat the saving throw using their spellcasting ability modifier. On a failure, the slot is expended, but the spell does not take effect. The target also then takes 2d8 necrotic damage per level of the slot expended On a successful save, the spell is cast as normal and the creature takes only half damage.

After three successful saving throws, this effect ends for that creature. After three failed saving throws, the creature is rendered unable to cast spells until they complete a long rest. These successes and failures do not need to be consecutive, keep track of both until one of the two is reached.
Usable by: Cleric, Sorcerer, Warlock, Wizard