Chicken fight
Chicken fight, also known as shoulder wars, is an informal game, often played in a lake or swimming pool, characterized by one team member sitting on the shoulders of his or her teammate or riding piggy-back. The object of the game is knock down or separate an opposing team through a team effort. The person on top is considered to be the "attacker" while the person below is considered to be the "vehicle". The person below may not use arms or hands and must rely on momentum to attack by running into the other team. The person on his/her shoulders is the "attacker" and may use any means possible of separating the other team or knocking them to the ground. If a team is separated or knocked down in any way, they are required to resign from the game and the last team to remain together is considered the winner. It is not uncommon for this game to be banned in many swimming pools due to safety concerns.
A similar Japanese game called "kibasen" (literally "cavalry fight", 騎馬戦) is commonly played as part of a school sports day events. It is a field event rather than a swimming event. In it, a team of four competitors work together, with three carrying the fourth, who wears a bandanna (hachimaki). The team is defeated if they are knocked over or, more commonly, if their bandanna is removed by an opponent.
In Brazil this game is called "briga de galo" (literally "cockfight").
In Mexico it is known as "Camel Fighting".