Stone (or more commonly: Pebble) is one of the advanced options in Rock Paper Scissors, used to discern the patterns in your opponent's psych (while confusing them of your own) rather than simply win. The advanced options are:

Pebble: Index and middle fingers sticking out, but curled, and thumb resting on curled index finger. Variant of rock; Ties with both Rock and Scissors, but loses to Paper.
Cardboard: Same as paper, but all fingers curled. Variant of Paper; Ties with both Paper and Rock, but loses to Scissors.
Key: Middle and Ring-fingers sticking out. Variant of Scissors; Ties with both Scissors and Paper, but loses to Rock.

All 3 are largely useless unless both parties involved have degrees in psychology, and take R-P-S far too seriously.

Are you saying that if you study psychology you would be able to win every rock scissors paper game?

Yes, if you're good enough at it (though, not EVERY game, but your win percentage will go up considerably). Training your eyesight and reflexes will help a great deal as well.

holy **** , i'm gonna study psychology

God damn it, you killed Buzz!

Whoever thought of that is a ******* idiot.

Essentially pebble, cardboard and key cannot win against rock paper or scissors.

Plus when you're playing a game of Rock paper scissors you count down 3,2,1 ... or some other method of counting down so everyone knows to go at the same time...

Who is seriously going to have time to methodically go with pebble cardboard or key? Let alone know which is going to win against what...

black people

This guy.

I dunno what they're talking about. I think blue-eyed Benjy is awesome.

remind me of the one with "i wanna **** you up the ass" lines and ends with "i would, if i could, bitch"