Copyright (c) 2001 Michael Albert, J.P. Grossman, and Richard J. Nowakowski

This game is played on an empty square board, with the following setup:

CLOBBERING - On each turn, each player must move a stone into an orthogonally (no diagonals) adjacent cell with an enemy stone, thus clobbering it (removing the enemy stone from the board)
GOAL - The player who makes the last move, wins
An example

Black to play. With the move d4:d3, Black wins in 4 moves. If White captures with c4 then Black reduces White's moves with d1:e1. If e1:d1 then c5:c4. 

All other possible captures have winnable responses. 

There is a ZRF to play Clobber with Zillions. To read more, check this site, and follow the research made on this game. Check Konane, a similar goal with identical setup and based on the same idea. Gregory van Patten sent me the following note: [...] this type of opening almost defines a special class of games. One is tempted to group together all games based on this "patchwork configuration". It is a good way to introduce the maximum level of interaction, fairly, at the start of a game. I like how both "Clobber" and "Konane" forbid diagonal moves, forcing only the simplest dynamics.

A variant is Cannibal Clobber , where the player can also capture its own stones.