During the Battle Phase, when a Spell/Trap Card is activated (Quick Effect): You can negate the activation, and if you do, destroy that card, and if you do that, this card gains 500 ATK
79699070 Curse of Tri-Horned Dragon 681
Arceus is classified as a 3-Diamonds card in the Triumphant Light set
Creating as many goblins as you can to fuel Krenko is key, from Dragon Fodder to Mogg War Marshal, combined with haste enablers, and effects to make sure they connect (like the flavourfully named Goblin War Drums)
These theories came from datamined hidden accessories in the in-game shop, which included references to Lugia and Pichu
Beyond Booster Box Magic Assassin's Creed Keep track of your collection value over time