When a card in Magic: The Gathering gets banned across the board, you know something went wrong somewhere.
Usually for a card to be banned it has to be detrimental to gameplay, have a ridiculous mechanic such as ante, or be a one that simply makes things too difficult for players.
In 1993, Magic's first expansion, Arabian Nights, came out and included a card that was eventually banned because it could extend game times. Like, by a lot. As in a lot a lot a lot.
The card's name? Shahrazad. And what did it do that made it one of the most disliked cards ever? Well, it made you play a game of Magic literally within a game of Magic. As in, "Yo dawg, I heard you like Magic. So I put some Magic in your Magic so you could play Magic while playing Magic."
Seriously, it was that. Take a look at the cards text:
"Players must leave game in progress as it is and use the cards left in the libraries with which to play a subgame of Magic. When subgame is over, Players shuffle their cards, return them to their libraries, and resume game in progress, with any loser of subgame halving his or her remaining life points, rounding down. Effects that prevent damage may not be used to counter this loss of life. The subgame has no ante, using less then 40 cards may be necessary."
Or, for the game's cleaner and updated Oracle text:
"Players play a Magic subgame, using their libraries as their decks. Each player who doesn't win the subgame loses half their life, rounded up."
Just one extra game of MTG within an existing game was annoying enough despite the payoff of the loser losing half of their life total. But the real problem was that the card could cause a multiplier effect by, say, playing Shahrazad within an already in-progress Shahrazad game. Or copying by means of something like Fork.
Throughout the 1990s and most of the early-to-mid 2000s, the problems quickly presented themselves. By 2008, due to new time restrictions, Shahrazad received bans in Legacy and Vintage tournaments and, in 2011, banned completely in EDH. Today, besides players crazy enough to want to experience this in casual play, it just isn't seen, all because MTG creators did not want games to last hours and have dozens of games of Magic within a game of Magic.
One player even calculated it. With the maximum number of cards allowed, you could have hundreds of minigames within one bigger game. It's like some sort of crazier version of Inception or something!
To date, no card coming even close to what Shahrazad had was ever printed, nor was the card ever reprinted. Not in black bordered Magic, at least (give a nod to the Unhinged card Enter the Dungeon).
In some regards, the card is just another example of how unusual early-Magic could get. But, on another level, it was a card that could essentially doom you and your opponent to play hundreds of games for a single win, making it a very forfeit heavy card. You know, for those who would want to win that way.
These days, the only winners with Shahrazad are the collectors. Currently (according to TCGPlayer's Market pricing), it's worth roughly $540.00.