Summon Over (SAST-EN070) - Savage Strike Unlimited

Each time a monster(s) is Special Summoned, place 1 Summon Counter on this card (max. 6). This card with 6 Summon Counters cannot be destroyed by card effects. At the start of each Main Phase 1, if this card has 6 Summon Counters: The turn player can activate this effect; they send this card to the GY, and if they do, they send all Special Summoned monsters their opponent controls to the GY.