The company that printed it made the card as part of a set of concept cards to present in order to get a full printing order
Crew 4 (Tap any number of creatures you control with total power 4 or more: This Vehicle becomes an artifact creature until end of turn.) Eternity Gate Whenever this Vehicle attacks, mill three cards
Tabak similarly emphasizes that high impact is a priority for these Unknown cards, because [people] have to be immediately wowed and immediately inspired to build decks around them. Thats due in part to the unique format Verhey has developed for Unknown over the dozen or so times its been run since its inception in 2023
Rainbow rare cards are unique to a particular part of Pokemon history, and the latest sets dont even have them
Unsurprisingly enough, most of these wincons require quite a bit of set up, and it's going to be a tall order to include enough cards to make any one of them properly viable
As Powerstones cant be used to cast nonartifact spells, youll need to rely on either artifact creatures or activated abilities to get your board big enough to win