Doomsday by paying ({B} magic symbol) ({B} magic symbol) ({B} magic symbol) , searching your library and graveyard for
Gush,
Gitaxian Probe,
Lion's Eye Diamond,
Yawgmoth's Will and
Laboratory Maniac, then exiling the rest of your library and graveyard, putting the aforementioned cards on top of your library in that order, and causing you to lose half your life total, rounded up.
Draw
Gush from the top of your library.
Cast
Gush by returning two Islands you control from the battlefield to your hand, causing you to draw
Gitaxian Probe and
Lion's Eye Diamond.
Cast
Lion's Eye Diamond by paying ({0} magic symbol) .
Cast
Gitaxian Probe by paying ({UP} magic symbol) .
Holding priority, activate
Lion's Eye Diamond by sacrificing it and discarding your hand, adding ({B} magic symbol) ({B} magic symbol) ({B} magic symbol) .
Resolve
Gitaxian Probe, causing you to look at a player's hand and draw
Yawgmoth's Will.
Cast
Yawgmoth's Will by paying ({2} magic symbol) ({B} magic symbol) , allowing you to cast spells from your graveyard this turn.
Cast
Lion's Eye Diamond from your graveyard by paying ({0} magic symbol) .
Activate
Lion's Eye Diamond by sacrificing it and discarding your hand, adding ({U} magic symbol) ({U} magic symbol) ({U} magic symbol) .
Lion's Eye Diamond is exiled instead of being put into your graveyard due to
Yawgmoth's Will.
Cast
Gitaxian Probe from your graveyard by paying ({UP} magic symbol) , causing you to look at a player's hand and draw
Laboratory Maniac.
Gitaxian Probe is exiled instead of being put into your graveyard due to
Gush from your graveyard by returning two Islands you control from the battlefield to your hand, causing you to draw two cards and win the game due to drawing from an empty library.