At least one of your opponents is unable to block Atemsis.
You have at least one additional card in hand.
You have at least one white card, blue card, black card, red card, and green card in library that together do not share a mana value with each other or at least one of the additional cards in hand.
Steps
Cast Conflux, searching your library for a white card, blue card, black card, red card, and green card in your library that together do not share a mana value with each other or at least one of the additional cards in your hand.
Attack an opponent who is unable to block Atemsis with Atemsis.
On damage, Atemsis triggers, allowing you to reveal your hand and losing that player the game.