As per local legend, Uparisiravasu, a king obtained boons after severe penance for years from Brahma that would enable him to fly with his chariot. While flying at this place, his chariot (locally called ther) fell in waters and splashed on sage Agasthya who was doing penance. The chariot got stuck in the place and hence it came to be known as Theranzhundur (where the chariot got immersed). Another variant, Uparisiravasu ruled in favour of celestial deities against the sages and the sages cursed that his chariot would not any further and it got stuck in the place. A third variant notes that the king did not heed the request of her queen to get down to worship Vishnu at this place while flying in his chariot and on account of divine powers his chariot was held at this place.