In the Hindu epic Ramayana, the Chandrahasa is an indestructible sword that Shiva gifts Ravana.
[1][2][3][4] The Uttara Kanda of the Hindu epic Ramayana records that the ten-headed, twenty-armed mighty King Ravana defeated and looted Alaka – the city of his step-brother and god of wealth Kubera, situated near Mount Kailash.
After the victory, Ravana was returning to Lanka in the Pushpaka Vimana (the flying chariot that his father in law made for him), when he spotted a beautiful place.
Nandi informed Ravana that Shiva and Parvati were enjoying a dalliance on the mountain, and that no one was allowed to pass.
In turn, Ravana decided to uproot Kailash, infuriated by Nandi's curse and his inability to proceed further.