Nineteenth-century melas (fairs) were evanescent public spaces that facilitated anonymity and unplanned encounters between castes, classes, men and women. By recognizing caste-passing in various mela clusters, historians gain insights into a range of subaltern debates about caste. Caste-passing involved lower caste adoption of the accouterments of upper castes and threatened social hierarchy. Opaque to police, associational life within fairs signified a society undergoing transformation. The figure of the Pardhan blacksmith embodied the unknowable fair-going crowd. Hailing from an adivasi (indigenous) community in the Central Provinces of India, these blacksmiths attracted police notice. Pardhan blacksmiths deployed their skills towards manufacturing imitation gold; at the fair they passed off as members of upper castes. For the police, Pardhan caste-passing within fairs threatened to unravel taxonomies of tribe and caste, region and religion. It was at the fair that hounded and persecuted Pardhan blacksmiths found some respite from the theft of their lands and labour. Through an analysis of caste-passing, a social history emerges of nineteenth-century fairs in colonial India that foregrounds experiences of those fairgoers who were members of ‘criminal tribes’ persecuted by colonial police, and the plebeian multitude that mingled in melas and participated in anti-caste debates.