They retain whatever format legality they had before their special guest selection
Just casting this will probably give you something back from your graveyard, and if you already have a mill engine going or dredge cards in your graveyard, the hell gates are open
This thing wears equipment very well, for example
I have always found the five mana Tezz to be vastly more effective, you are typically playing artifact ramp with either and so the coloured mana is harder to get than the colourless portion making the five mana Tezz easier to play
For Mewtwo master collectors worldwide, the JPN S10B box is the only sealed product that can produce a Mewtwo V Special Art
For example, I saw a store purchase the Umbreon VMAX CSR for quite a lot of money under the mistaken impression that it would be worth as much as the Sword & Shield Evolving Skies Umbreon VMAX