The Moolavar is Yadokthakaari, Sonnavannam seidha Perumal (sonnavannam - as told; seidha - did) seen in bujanga sayanam posture facing west. Once, when Thirumazhisaialwar called him, The Lord is said to have taken his snake bed & travelled to see him. Then when Thirumazhisaialwar asked to lie on his sanke bed, he did that too. Hence the name Sonnavannam seidha Perumal.
The asuras bade vegavathi river to run in full spate & destroy the yagna of Brahma. The Lord controlled the fury of the Vegavathi river in spate. This is the avataara sthalam of Poigaialwar.
Thaayaar - Komalavalli Naachiyaar.
Theertham - Poigai Pushkarini.
Thirumazhisaialwar - 814, 815, 2417
Thirumangaialwar - 1854, 2059, 2064, 2065, 2673 (70), 2674 (127)
Poigaialwar - 2158
Peyalwar - 2307, 2343, 2345, 2357
Nammalwar - 2503
Total of 15 Paasurams