It's legal in Legacy, Vintage, and Commander, so this is a card you can realistically get to the table - providing you can afford to buy a copy
Whether you were playing the games, trading the cards, or as I did quite literally pretending to be Pokemon with your friends, Mewtwo's place was well-established as the greatest of all time
And given that its Pok-BODY forces an opponent to discard a card if they wish to attack, its mere presence on the field can destroy many strategies
Its kind of skill testing and rewards precision, just like the ninja at the head of the deck, so its fun to play
Id like to imagine I could have found one alt-art in all those cards, but obviously the sample size is too small to draw conclusions from, and I may have just been spectacularly unlucky