Crown of Thorns
Level 4 · Enchantment · Ritual · Concentration
You create a psychic binding on the mind of a creature within range. Until this spell ends, the creature must make a Charisma saving throw each time it casts a spell. On a failed save, it takes 2d6 psychic damage, and it fails to cast the spell. It doesn't expend a spell slot if it fails to cast the spell.