Magic The Gathering: cEDH

cEDH, or competitive Elder Dragon Highlander, refers to a sub-format of the popular Commander format that's specifically targeted towards competitive cards, decks, and players. cEDH is known for having much more cutthroat playstyles and strategies that almost always revolve around an infinite combo to win the game.

There aren't any official WotC rules for cEDH so there's still some room for Rule 0-type changes at your local game store. Commander has a wide variety of cards available which makes a long list of combos and styles that are generally “unfun” or overwhelmingly powerful. Since EDH is meant to be a casual format, these high-power decks and strategies have been grouped into their own category so that players know what they’re getting into and don't get run over.