pokemon card x - Salamence LV.X (98) - Arceus or pulls cannot be guaranteed The Company You Can Pay

Why did the creatures have to be able to change back and forth

With four copies of Gholdengo ex in the deck, it becomes very easy to keep your hand full of cards

Fable Of The Mirror-Breaker A Smash Hit Neon Dynasty saw the introduction of double-sided transforming Sagas, that flip into a creature on their last chapter

They can technically eliminate that hassle by setting up a US base or other international bases but there is no current demand (and may never be enough demand) to warrant that

I believe an early version of this card experimented with each Zombie getting to give -1/-1 to target creature until end of turn, but that ended up being too powerful, and the spell would often decimate the other side when cast late in the game

You'll put a time counter on it at the beginning of your upkeep, and once you have at least one you'll be able to Time Travel (or proliferate) them to either of your hearts' content!