This is a Jeevasamadhi of Arumuga Swamy Siddhar. There are various jeevasamadhis in the temple premises.
There is a place to sit and meditate. You can go into meditative states here effortlessly.
How to get there
It is located 10 kms North of Kumbakonam.
Map: https://goo.gl/maps/8iyWbMTfmHH1NVpx8