Mordenkainen's Lost Notebook

Otiluke’s Suppressing Field

4-level Abjuration (ritual)

As you cast this spell, your skin tingles as you radiate a field of powerful magic. The field extends from you in a 20-foot-radius sphere. Choose a school of magic (such as conjuration or evocation). Spells of that type are suppressed within the area of your spell. Any creature attempting to cast a spell of that school in or into the area must succeed on a saving throw using it spellcasting ability, with a DC equal to your spell save DC. On a failed save, the spell fails.