Shambuka (Sanskrit: शम्बूक, IAST: śambūka) is an interpolation in Valmiki Ramayana. According to the story, Shambuka, a shudra ascetic, was killed by Rama for attempting to perform tapas in violation of dharma, the bad karma resulting from which caused the death of a Brahmin's son.
This story is treated as a later interpolation to Valmiki's Ramayana, being created at a later period in opposition to Brahmins. It is found in the Uttara Kanda, which is the final section of the text.
When Rama was ruling Ayodhya, a Brahmin approached the court and told everyone that his young son has died due to the misrule of Rama. Rama immediately called a meeting with all his ministers and enquired about the cause of this. The sage Narada told him that this has happened due to violation of a rule of tapas (austerities). Narada informed him that a shudra was performing tapas, which was prohibited. So Rama went in search of the shudra and found the place where Shambuka was performing penance. After confirming that Shambuka is indeed a shudra, Rama killed him. The gods praised Rama for this act and congratulated him for protecting their interests and for not allowing shudra to attain heaven. Brahmin's son was also resurrected.
Authors such as Rabindranath Tagore, Mahatma Gandhi treat the character of Shambukha as interpolation. The Pushtimarg Vaishnavite tradition points out that the Ramayana refers to other shudras, such as Shabari, who lived in the forest. Shambuka therefore deliberately violated dharma in order to get Rama's attention, and attained salvation when he was beheaded. The celebrated Kannada poet Kuvempu, in his play Shudra Tapasvi shows Rama as having to both carry out his duty by punishing Shambuka, and simultaneously protect Shambuka, as a pious and devout sage, from persecution, and thereby turns the story into a critique of Brahminical attitudes and a defense of Rama.
In his seminal work Annihilation of Caste, B. R. Ambedkar points out the story of Shambuka while criticizing the varna system. He argues that not only it is impossible to accurately classify people into four definite classes but that the varna system faces the problem of the transgressor. He further explains that unless the transgressor is punished, men will not keep to their respective classes i.e. the whole system will collapse. In the Ramayana, according to Ambedkar, Rama ensured that transgression did not happen in his kingdom by killing Shambuka.
By now , it can be confirmly said the ' Uttarkand ' of Ramayana is an interpolation of quite later period
Mahatma Gandhi , on the other hand, has regarded this entire story as an interpolation