The previous expansion, Celestial Guardians, focused on Alolan forms and Trial Captains
Its Max Jammer attack deals a strong 180 damage (perfect for two-shotting opposing VMAXes) and the effect allows you to take the most important card in your opponents hand and put it on the bottom of their deck
These will quickly build up into an insurmountable force to devour your opponents
However, Arceus's " Starbirth " - which allows players to pick two cards from their deck and then shuffle - is an incredibly strong ability
Six mana can be a lot, but red has no shortage of rituals or Treasure tokens to get this out early, and while you cant cascade from copies of spells, you can discover if you cast cards like Trumpeting Carnosaur or Hit the Mother Lode, which then gives you more copies
Furthermore, according to the description from the auction listing on Heritage Auctions' website: Featured here is the theatrical released promo card known as Ancient Mew