Pippalada

Pippalada was a sage and philosopher in Hindu tradition. He is best known for being attributed the authorship of the Prashna Upanishad, which is among the ten Mukhya Upanishads. He is believed to have founded the Pippalada school of thought, which taught the Atharvaveda. He is regarded to be an incarnation (āṃśa) of Shiva in some Puranas.