Shiva Tandava Stotram is a Hindu hymn that describes the God Shiva's power and beauty. It is traditionally attributed to Ravana, the demon king of Lanka and devotee of Shiva. Both the ninth and tenth quatrains of this hymn conclude with lists of Shiva's epithets as destroyer, even the destroyer of death itself.
Ravana, the demon king,was obsessed with his powers and was egoistic, and to display and prove his powers he was about to move Mount Kailash (the abode of Shiva who was his ancestor God). He managed to lift the mountain but Shiva immediately placed it back just by pressing his toe crushing Ravana's fingers in the process. That is when Ravana sings "Tandav Stotra" and he was spared and blessed with chandrahas (moon sword by Lord Shiva) considered one of the most powerful weapons in Hindu Mythology.
In the final quatrain of the poem, after tiring of rampaging across the Earth, Ravana asks, "When will I be happy?" Because of the intensity of his prayers and ascetic meditation, of which this hymn was an example, Ravana received from Shiva powers and a celestial sword.