That's a deliberate 30th anniversary play
Beyond the most obvious useif youre using attacks that are boosted by the number of cards on the opponents benchif someone is leaving space for their vital Ralts to support their Mewtwo, or a Charmander that stubbornly wont come out to build their Charizard, filling that slot with whichever card they sacrificed up front would be extremely funny.
While this allows players to special summon every card in the Spright archetype from the GY, it also allowed the Tearlaments strategy to continue their combos by bringing back Tearlaments Merrli from the GY
At the end of their turn, the player flips a coin - on a head, the Pokmon wakes up and is no longer asleep
Tiras, Keeper of Genesis has a Trigger Effect that allows it to destroy 1 opponents card after it battles at the end of the Battle Phase, and it could be used to Xyz Summon Gaia Dragon, the Thunder Charger and then Divine Arsenal AA-ZEUS Sky Thunder during Main Phase 2
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