In the Indian epic the Mahabharata, the minor character of Aravan, the son of Arjuna and Princess Ulupi, has become a cult figure in several areas of India. In southern India he is worshipped in the cult of Kuttantavar, which is the name the cult gives him. In the Mahabharata, he dies a heroic death in the war that is the centerpiece of the epic.
The cult sees his death as a self-sacrifice to the goddess Kali to ensure that the triumph of his family, the Pandavas. In return for his sacrifice, he was granted his wish to be married (so he could be cremated, since bachelors were buried and not cremated) by Krishna, who took on his female form, Mohini, and married him for one night.
The cult, which is practiced in Tamil Nadu, includes an 18-day festival at Aravan’s main temple in Koovagam in which the village men and transgender “eunuchs” from the surrounding area dress up as women, performing a ritual marriage and then observing the rites of widowhood, worshipping the severed head of Aravan. The festival has also long attracted transsexuals from all over India – some 25,000 currently attend – and even farther afield, from as far away as Singapore.
Kshetra Puranas and Other Stories blog has a page on the Kuttantavar festival, here.