The serpent is conspicuous by its absence in Harappan seals, and in Ashokan artworks. Serpent worship is not part of Vedic texts. Multi-headed hooded serpents first appear in Buddhist shrines, at Sanchi and Bharhut. They appear as adoring symbols of Buddha. Then, the serpent-gods are shown sheltering the Buddha and the Tirthankara under their hood. 

Coiled serpents and inter-twined conjugal serpent pairs appear as sacred symbols on Hindu temple walls. They reflect sacred ideas from beyond the Vedic world, where communities venerated serpent groves, filled with termite mounds, which served as entrances to a subterranean world of magical beings — the Naga, serpents with hoods, multiple heads, and the magical ability to appear as humans. 

Naga was linked to water bodies, to fertile earth, to child-bearing, health, restoration of youth, to magical gems, to occult secrets, to all things hidden under the earth and beneath the conscious mind. Today we cannot imagine Hinduism without Nagas.