Don't go bringing these cards to a Standard game because, while your deck will undoubtedly be the best at the table, it'll also be illegal
Holactie is a very important part of the anime, and a very cool part of the card game, too
The basic summary explanation how these could be produced in 1995 is Creatures/ Game Freaks history from the beginning of always labeling Copyrights on cards as well as the lack of Mew in the set
A total of 19 cards were given this treatment and one card, the Buy-a-Box card, only exists in its Godzilla Series form, but each of the others has both an Ikoria card and a matching Godzilla Series card. Heres how you can get your hands on these Godzilla Series Monster cards:
for the rest of the turn, you cannot Normal or Special Summon monsters, except Abyss Actor monsters, also Special Summon the targeted card, then take from your Deck or face-up Extra Deck 1 Abyss Actor Pendulum Monster with a name different from that Special Summoned monsters, and if you do, place it in your Pendulum Zone
Cosmog (PROMO-A) is not available in Regular Packs