The centuries old festival coincides with El Día de los Inocentes on December 28th, which marks the biblical Massacre of the Innocents by King Herod.
Under the slogan of 'New Justice', a group of married men take siege of the Valencian town and impose a series of ridiculous laws on residents.
Those who don't abide by the new laws set by the Enfarinats, the 'Flour Police', are given unofficial fines.
A battle of eggs, flour and firecrackers is then waged between the Enfarinats and La Oposició, another 'army' which tries to restore order in Ibi.
At the end of the day, all the money collected from the 'fines' is donated to charitable causes in the town.
The bizarre fiesta has been traced back to at least 1862 when the first such celebration was held in the town. But it stopped when real fighting broke out across Spain during the Spanish Civil War of 1936-39 and wasn't resumed until 1981, six years after the death of dictator General Francisco Franco.