Kotodama (SRL-095) [Spell Ruler]

If there are face-up monsters with the same name on the field, destroy those monsters. (If a monster is Summoned or flipped face-up that has the same name as a monster that is already face-up on the field, the new face-up monster is destroyed. If they are Summoned or flipped face-up at the same time, they are all destroyed.)