Story of Kannappa is mentioned in the Peria Puranas. Kannappa was one of the 63 Tamil Saints – the 63 Nayanars. Before becoming a saint, Kannappa was known as Thinnan and he was a hunter by profession.
Thinnan was attracted to Shiva and he was an innocent devotee. He had no knowledge about rituals and pujas. So he used to offer flowers, water and flesh of the animals he killed to Shivling.
To the society, Thinnan’s offering were impure. But Shiva accepted them because it was offered with devotion and with no malice. Purity of devotion made the offering the best.
One day Kannappa noticed that one of the eyes of the Shivling was bleeding. He tried to cure the bleeding eye with herbs. But it did not work. As his efforts failed, Kannappa plucked his one eye and transplanted it on the lingam. Then suddenly the second eye of the lingam began to bleed. Kannappa plucked his second eye and transplanted it on the lingam.
Pleased with his devotion, Shiva gave darshan to Kannappa and restored his both eyes. He was also given the boon of eternal presence of Shiva. He then became a Shaiva Saint.