Rock-paper-scissors-lizard-Spock is an expansion of the classic selection method game rock-paper-scissors. It operates on the same basic principle, but includes two additional weapons: the lizard (formed by the hand as a sock-puppet-like mouth) and Spock(formed by the Star Trek Vulcan salute). This reduces the chances of a round ending in a tie (from 1/3 to 1/5). The game was invented by Sam Kass with Karen Bryla, as "Rock Paper Scissors Spock Lizard".