Scum is a game of trying to rise in the social order. One player is the president. The others are in decreasing social position, with the lowest player being scum.
The object of each round is to deplete your hand of cards. Whoever does so first will be the new president down the line until the last one out becoming the new scum. The game is weighted so that those who are higher up in the social order will have a playing advantage over those below them, so it will take skill to rise to a higher position.
Players of Asshole (Scum: The Food Chain Game) or The Great Dalmuti will recognize the basic mechanics of Scum. Scum adds trump cards of the President and the Wild president to the standard numbered cards. Also, there are variants that cause the color of the cards to have impact on the game play.