Playing an Eight of any suit irrevocably skips the next player.
In a two-player game, the Eight has the same effect as an Ace, in the sense that the player who plays the Eight immediately plays again.
Expert info: However, there is an important difference between Aces and Eights, that even in a two-players game it is allowed to end the game with an Eight. This is because the Ace is a self-reflecting card, that resets the turn in-place and forces the player to play again immediately. On the other side, the Eight switches the turn to the next player, and if it was the last card the game is ended, with no time left for the turn to come back.