Constance's Forgetfulness

The spellcaster causes creatures within the area of effect to forget the events of the previous minute of time from the utterance of the spell. Naturally, Constance's Forgetfulness in no way negates any school of enchantment spell, but it is possible that the creature who caused such magic to be placed upon the victim of this spell could be forgotten by this means.

From 1-4 individual creatures can be affected by the spell, at the discretion of the caster. Each creature over the first gains a +1 to their saving throw. A Greater Restoration spell, specially cast for this purpose, will restore the lost memories, as will a Wish, but other means will not serve to do so.

Casting at higher Levels: Casting this spell using a spell slot of 2 or higher has can have one of two effects. 

The duration of time forgotten is increased as follows: 2nd = 5 minutes, 3rd = 10 minutes, 4th = 15 minutes, 5th = 30 minutes, 6th = 1 hour, 7th = 1 day, 8th = 1 year and finally 9th = 1 lifetime.

or

The number of affected creatures is multiplied by the slot number. Example: Casting this spell at 4th level can affect up to 16 creatures within a 20-foot cube. Every creature after the 4th creature gains an additional +1 to their saving throw, ending with the last creature having +12 to resist the space.