Activate 1 of these effects.

● When your opponent activates a Spell/Trap Card while a "Dream Mirror of Joy" is in a Field Zone: Negate the activation, and if you do, destroy that card.

● When your opponent would Special Summon monster(s) while a "Dream Mirror of Terror" is in a Field Zone: Negate the Summon, and if you do, destroy that monster.

You can only activate 1 "Dream Mirror Oneiromancy" per turn.