Rumassala, known to Portuguese as Buona Vista, is the subject of many legends. It is featured in Valmiki Ramayana, where the monkey chief of Rama Hanuman is dispatched to fetch a medicinal plant “Sansevi” to save the life of wounded Rama, being unable to find it instead brought a part of the Himalayan mountains on which it was said to grow. He dropped a chunk at Unawatuna ('here it fell') to form the present mountain, where many medicinal plants still grow.
There is a major magnetic anomaly near Unawatuna, which Arthur C. Clarke attributes to a meteorite strike, and it is said that satellites lose their orbits with unusual frequency overhead.
The Portuguese had a dreadful reputation in Sri Lanka as looters and pirates, and are said to have given false light signals from Rumassala to lure unsuspecting Arab trading ships onto the rocks.