Mental Vapors

House Dimir Spell
Level 3 or 4 (?)
Casting Time: 1 Action
Duration: Instantaneous
Range: 80 ft (?)
Target Humanoid within range must make an Intelligence Saving Throw. Regardless of whether or not the Save is successful, the caster gains knowledge of all the spells that are able to be cast by that humanoid. On a failed save, choose one leveled spell (of a level less than or equal to the level that this spell was cast at) that the target humanoid is able to cast, that humanoid is unable to cast that spell using one or more of their spell slots for 24 Hours.
Once under the effect of this spell, the effected creature cannot be targeted by this spell (no matter who it was cast by) for the next 24 hours.