There are 2 'Paadal Petra Sthalam' in the name of Tirumullaivayil. To differentiate them, the one located in Thondai Nadu is known as Vada-tirumullaivayil and other one near Sirkazhi is known as Then-tirumullaivayil (North of river Cauvery).
Sthala Puranam - A Chozha king named Killi Valavan-1 sufferred from a skin diesease. When the royal physicians, for remedy, suggested bathing in a waterbody that was near a Shiva temple, the king along with his entourage, came to the sea-shore near this temple to take baths. In those days, this area was heavily overgrown with a creeper known as 'mullai', which ensnared the hooves of their horse, rendering it immobile. When Killi Valavan attempted to sever the vines with his sword, he inadvertently struck a Shiva Linga concealed beneath the foliage, causing it to bleed. Alarmed by the blood, the king mistakenly believed he had harmed a living creature. Upon carefully clearing the vines, he discovered the bleeding Linga, which horrified him to the point of contemplating suicide. According to the Sthala purana, Shiva then appeared before the king in the form of 'Rishabarudar', and the mark from the sword remains visible on the Linga to this day.
Sculpture depicting the Sthala Purana
Tirumullaivasal is a coastal temple situated on the northern bank of the Uppanaru River. The temple is characterized by a modest entrance that lacks an elaborate gopuram. Beyond this entrance, one can find a Nandi mandap, a dwajasthambam, and a balipeetam. The principal deity, Mullai-vana-Nathar, is represented by a three-foot 'swayambhoo Linga' and is also known as Masilamani Eeswarar and Yoothika-Parameshwarar. The temple comprises a single prakaram that contains sannidhis for Varasidhdhi Vinayaka, Shanmukha Subramania with Valli-Deivanai, Dakshinamurthy, Bhairavar, and Tirugyanasambandhar. Dakshinamurthy is depicted beautifully and is so divine. The 'sthala vruksham' is the Mullai tree, and the sacred water bodies are Brahma theertham and Chandra theertham. Lord Shiva serves as a guru in this temple, as the goddess worshipped Mullai-vana-Nathar to gain knowledge of the sacred Panchakshara Mantra. A note-worthy feature of this temple is the absence of 'Palli-arai' and its related rituals. The 'palli-arai' is absent here as Uma Devi learned the sacred mantra directly from Dakshinamurthy in a student-teacher dynamic. It is believed that those who visit and chant the Panchakshara Mantra during solar and lunar eclipses will be liberated from the cycle of rebirth.
Ganga is said to be eternally present in the well located in the north-west corner of the temple, known as 'vayu moola.' Chandra, the celestial deity associated with the moon, is believed to have bathed in the Brahma theertham situated in the south-west corner, referred to as 'Agni Moola,' in order to heal from his affliction.
The pathikam composed by Tirugyanasambandar is in 2'nd tirumurai.
Entrance
Mullai-vana Nathar sannidi entrance
Satyananda Sundari sannidhi entrance
Dakshinamurthy
Nandi, Balipeetam