Doomsday decks use the namesake sorcery to exile all but five cards from their library and graveyard, then arrange those five cards into a carefully engineered pile designed to win the game more or less right away.
Cards such as Gitaxian Probe, Gush, and Lion's Eye Diamond can help draw through or manipulate a Doomsday pile, while Thassa's Oracle gives modern versions an extremely compact payoff for achieving victory through an empty library.
