Exodia

5 separate Yu-Gi-Oh! cards, that when combined, allows you to instantly win the game for some reason. Is it overpowered, yes. Is it unfair, yes. Would it make the game unplayable if you weren't only allowed to have one copy of each Exodia piece in your deck, absolutely. But is it frickin cool, hell yeah it is!

Kaiba: Draw your last pathetic card so I can end this Yugi!

Yugi: My grandpa's deck has no pathetic cards Kaiba... But it does contain, the unstoppable Exodia!

Kaiba: Aaagh!- Impossible!-

Yugi: I've assembled all 5 special cards, all 5 pieces of the puzzle!

Kaiba: Exodia!- Ahhhhh!- It's not possible!- No one's ever been able to call him!-

Yugi: Exodia, obliterate!!!

Kaiba: Ugh!- Ahhhhhhhhh!-

*noises of kaiba fucking dying*