Dimension Fusion was released in 2004 as apart of Invasion of Chaos but ended up needing an emergency ban in 2008. This brings up the question, “Why is Dimension Fusion Banned?”
What does Dimension Fusion do?
Dimension Fusion has a simple effect and drawback. In order to play this card, the player must pay 2000 life points. Then both players can special summon as many banished monsters as possible. Then, the turn continues, and typically causes a huge swing. The ideal case is to pay 2000 LP to trigger the effect of this card then unleash a whole board of monsters in order to end the game in one turn. Players of Yugioh can probably think of how useful this card is, and the downside is not that bad in most cases. The card is just plain good.
The One Turn Kill
Dimension Fusion needed to be emergency banned. The OTK had four different cards take part, but Dimension Fusion was the facilitator and the best. The loop is as follows.
The first thing the player did was get Dark Magician of Chaos on the field. Then the player plays Cannon Soldier as well as Spell Economics. Cannon Soldier lets the player tribute one monster on the field to inflict 500 life points to your opponent. If Dark Magician of Chaos leaves the field it is banished instead. The player would then play Dimension Fusion to bring Dark Magician of Chaos back. However, the player doesn’t need to pay the life points because of Spell Economics. Then when Dark Magician of Chaos is summoned you can add one spell from your graveyard to your hand. This is Dimension Fusion.
The loop would then go on until the enemy had zero life points. This combo was incredibly degenerate, and Konami had to rush a ban list to get this out of the game. This is horrible to play against, and they made the right call.
Will Dimension Fusion Stay Banned?
Yes. An emergency ban list is rare, and even if the combo mentioned above is harder to pull off now the card is still good. Decks that banish cards would become way better if this is in the game. Keeping this out of the game is frankly better for the health of the game.
If you want to learn more about incredibly strong cards that created OTKs may I suggest this article on Butterfly Dagger – Elma?