Son of Kadru. Elapatra overheard a conversation between the Gods and Brahma. He assured that only the non-virtuous snakes would perish at Janamejaya’s snake sacrifice. Elapatra was able to calm the snakes.
To read about Elapatra visist
http://talesfrommythology.blogspot.com/2015/05/the-consumption-of-nagas-iv-bride-of.html