Rock-paper-scissors-lizard-Spock is a five-gesture expansion of the classic selection method game rock-paper-scissors

Rock-paper-scissors

Rock-paper-scissors is a hand game played by two people. The game is also known as roshambo, or another ordering of the three items ....

. It operates on the same basic principle, but includes two additional weapons: the lizard

Lizard

Lizards are a widespread group of squamate reptiles, with nearly 3800 species, ranging across all continents except Antarctica as well as most oceanic island chains...

 (formed by the hand as a sock-puppet-like mouth) and Spock

Spock

Spock is a fictional character in the Star Trek media franchise. First portrayed by Leonard Nimoy in the original Star Trek series, Spock also appears in the animated Star Trek series, two episodes of Star Trek: The Next Generation, seven of the Star Trek feature films, and numerous Star Trek...

 (formed by the Star Trek

Star Trek

Star Trek is an American science fiction entertainment franchise created by Gene Roddenberry. The core of Star Trek is its six television series: The Original Series, The Animated Series, The Next Generation, Deep Space Nine, Voyager, and Enterprise...

Vulcan salute

Vulcan salute

The Vulcan salute is a hand gesture consisting of a raised hand, palm forward with the fingers parted between the middle and ring finger, and the thumb extended. Often, the famous line, "Live long and prosper", is said after it. The salute was devised and popularised by Leonard Nimoy, who...

). This reduces the chances of a round ending in a tie compared to the more traditional game. The game was originally invented by Sam Kass and Karen Bryla. It was mentioned in an article of The Times

The Times

The Times is a British daily national newspaper, first published in London in 1785 under the title The Daily Universal Register . The Times and its sister paper The Sunday Times are published by Times Newspapers Limited, a subsidiary since 1981 of News International...

in 2005, and popularized in 2008 by "The Lizard-Spock Expansion", the 8th episode, Season 2 of the sitcom The Big Bang Theory

The Big Bang Theory

The Big Bang Theory is an American sitcom created by Chuck Lorre and Bill Prady, both of whom serve as executive producers on the show, along with Steven Molaro. All three also serve as head writers...

. In that episode, Sheldon

Sheldon Cooper

Sheldon Lee Cooper, B.S., M.S., M.A., Ph.D., Sc.D. is a fictional character from Texas on the CBS television series The Big Bang Theory, portrayed by actor Jim Parsons...

 introduces the game to his friends and, being avid fans of Star Trek, they all continuously put up the "Spock" sign.

Rules

The rules of Rock-paper-scissors-lizard-Spock are as follows:

• Scissors
  Scissors
  Scissors are hand-operated cutting instruments. They consist of a pair of metal blades pivoted so that the sharpened edges slide against each other when the handles opposite to the pivot are closed. Scissors are used for cutting various thin materials, such as paper, cardboard, metal foil, thin...
  
   cut paper
  Paper
  Paper is a thin material mainly used for writing upon, printing upon, drawing or for packaging. It is produced by pressing together moist fibers, typically cellulose pulp derived from wood, rags or grasses, and drying them into flexible sheets....
  
  
• Paper covers rock
  Rock (geology)
  In geology, rock or stone is a naturally occurring solid aggregate of minerals and/or mineraloids.The Earth's outer solid layer, the lithosphere, is made of rock. In general rocks are of three types, namely, igneous, sedimentary, and metamorphic...
  
  
• Rock crushes lizard
  Lizard
  Lizards are a widespread group of squamate reptiles, with nearly 3800 species, ranging across all continents except Antarctica as well as most oceanic island chains...
  
  
• Lizard poisons Spock
  Spock
  Spock is a fictional character in the Star Trek media franchise. First portrayed by Leonard Nimoy in the original Star Trek series, Spock also appears in the animated Star Trek series, two episodes of Star Trek: The Next Generation, seven of the Star Trek feature films, and numerous Star Trek...
  
  
• Spock smashes scissors
• Scissors decapitate lizard
• Lizard eats paper
• Paper disproves Spock
• Spock vaporizes rock
• Rock crushes scissors

There are ten possible pairings of the five gestures, where each gesture beats two of the other gestures and is beaten by the remaining two.