Viradha had a special power in that he could not be killed with any weapon. Knowing this fact, Rama grounded and stood on him. Laxman dug a moat, and Viradha was buried live.
Virādha (Sanskrit: विराध, Tamil: Viratan, Thai: Phirap, Malay: Purbaita) is minor character from the Aranya Kanda of the Ramayana. He is a rakshasa living in Dandaka forest who briefly kidnaps Sita in an episode that has been described as "strongly [prefiguring Sita's] later abduction by Ravana, the central event of the book and the pivotal event of the epic." Rama and Lakshmana begin to battle the monster, but though they shoot it with many arrows, the arrows pass straight through him and leave him unharmed (Aranyakada, Sarga 3). The monster reveals that he has a boon from Brahma which makes him invincible to weapons. So the brothers kill the rakshasa by first breaking his arms, then burying him alive in a grave. When the monsters arms are broken, he begins to praise the brothers for liberating him: he had, in a previous life, been a celestial being named Tumburu, and had been cursed by Kuvera to live as a fearsome monster until he be killed by Rama. The brothers bury him, and he apparently goes back to his former celestial abode.