Mud wrestling is classically defined as physical confrontation (fighting, wrestling, etc.) that occurs in mud or a mud pit. The popular modern interpretation specifies that participants wrestle while wearing minimal clothing and usually going barefoot, with the emphasis on presenting an entertaining spectacle as opposed to physically injuring or debilitating the opponent to the point where they are unable to continue the match. Venues for competition are usually social in nature with equal numbers of male and female spectators. Mud wrestling is typically performed in a semi-competitive fashion — though presented as a competition between participants, winning and losing is not considered as important as having fun.
However a mud wrestling scene appears in the 1972 film Cabaret. Though set in 1930s Germany and probably anachronistic for that period, the presentation of the scene suggests the film makers were at least aware of this as a contemporary form of entertainment which 1972 viewers might recognize.
For small events, a good analog for typical garden variety 'mud' is the use of sodium bentonite clay. Sodium bentonite - aka "Bentonite" is a well known additive in the food and cosmetic industries and is also used in the spa industry as the base for various mud masks, mud wraps and mud baths. Sodium bentonite (as opposed to potassium or calcium bentonite) has the unique property of expanding 15 to 18 times its original volume when hydrated with water. Thus a considerable amount of 'mud' can be synthesized from a relatively small amount of dry bentonite clay.
Bentonite is often available at well stocked clay and pottery dealers and can sometimes be found at various "farm and home centers" where it is used primarily to seal ponds. Clay and pottery stores often stock bentonite in 50 pound bags of very fine powder (ie 300 mesh or finer). Farm and home centers may carry bentonite as a fine powder, but a coarse 'chipped' variety is more common. Fine mesh bentonite is much more preferable as it produces a slippery 'mud' which is free from insoluble material and small rocks which may accompany the coarser 'chipped' bentonite.
It is also important to note that complete hydration of bentonite clay may take up to 24 hours once water is added to the dry clay. Thus, some amount of pre-planning may be needed when organizing an event. Additionally, use of bentonite alone, can result in a relatively translucent mixture. Other clays, such as kaolin or Old Mill #4 ball clay can be added to enhance the consistency and opacity of the mud if desired.
Approximately 100 pounds of sodium bentonite combined with 100 pounds of kaolin clay can cover the bottom of a 8' x 8' wrestling ring with several inches of extremely slippery, creamy-smooth mud. Proportions can always be adjusted larger or smaller depending on the amount of mud required and the consistency desired.
Another variation is Mashed Potato Wrestling, which is popular in Barnesville, Minnesota and Clark, South Dakota in the U.S.A
Another variation involves having the participants in formal dress, the entertainment value supposedly heightened by the ruining of expensive clothing.
In the movie Old School, an old man named Blue, who was part of a fraternity in the college in the film, died in a mud wrestling competition before it had even started. He probably suffered from a heart attack when the two women he was supposed to wrestle took their tops off.
Mud Wrestling was popularized in France by the TV game show Fort Boyard. In the 90s the Spanish TV game show El gran juego de la oca became highly popular in most Spanish speaking countries. In El Gran Juego de la Oca the participants played as pieces in a giant board game where they had to pass the test of the space where they landed. Next to space number 8 was a mud pit where participants had to complete a test while being disturbed by Romy, a model / female mud wrestler. The tests were different but with the main idea of the mud wrestling, they could go from taking gloves from a wall with hands, to completing a word by finding all the letters painted on the body of the mud wrestler.