
Pendulum Area
Normal Trap Card
(1) If the only monsters you control are Pendulum Monsters: You can target 2 cards in your Pendulum Zone; destroy those cards, and during this turn, neither player can Special Summon, except by Pendulum Summoning.
Well now pendulum decks can screw over non-pendulum decks. Could be a side deck card, could not see any play at all because it is a trap card and because of the activation requirement.