Slim boxes were the extra kindlarger than Jumbo boxes (yes, really), stuffed in a plastic sleeve to cradle the booster packs like fine china
At the beginning of each end step, if you gained 3 or more life this turn, create a 3/3 white Bird creature token with flying and "Whenever this token attacks, target attacking creature gains flying until end of turn." Whenever Gwaihir attacks, target attacking creature gains flying until end of turn
Sure, if the Stadium gets knocked out of play you have to discard those extra Pokemon, but it can definitely help with plenty of strategies to have as many Pokemon out as possible
Given how hard it is to enjoy this card's depiction of Reshiram, it's shocking that it commands so much value
Other cards with Gnaw Cards by Yuka Morii Frequently Asked Questions How can I obtain the Grubbin with 1-Diamond rarity from the Celestial Guardians set