Description
Chyawanprash is named after Rishi Chyavana, a sage who got blinded by a curious princess (Sukanya), married her as penance, was de-aged by the Aśvin twins, and then conjured a sky-swallowing demon, Mada, to strong-arm Indra into letting the twins drink Soma.
The story first appears lean and ritual-minded in the Shatapatha Brahmana (IV.1.5), where it exists mainly to explain why the Aśvins get their own Soma cup. The Mahabharata (Vana Parva) then expands it into full melodrama: the termite mound, the eye-poking, the husband-identification contest, the cosmic showdown.
Here's the oddity worth sitting with. The entire stage of Indra, the Aśvins, the Soma sacrifice is Āṅgirasa territory. The Aṅgirasas are Indra's own priestly clan, the singers of the agonistic, Indra-affirming Soma cult. Yet the agent who humbles Indra and rewrites who's allowed to drink Soma is a Bhārgava: Chyavana, son of Bhṛgu. The Bhṛgus seem to have draped their own framing over inherited Āṅgirasa material taking a Soma myth that structurally belongs to Indra's people and quietly recasting it so a Bhārgava sage wins, Indra kneels, and the priest out-ranks the god.
That's precisely the editorial fingerprint V.S. Sukthankar identified in "The Bhṛgus and the Bhārata" (1936): a guild of Bhārgava brahmins redacted the Mahabharata, idealizing their own ancestors, moralizing the narrative, and reshaping older myth so the Bhṛgu line always comes out on top. Sukanya's tale is that whole process in miniature.
Sources: Shatapatha Brahmana IV.1.5 · Mahabharata, Vana Parva · Sukthankar, Epic Studies VI (ABORI, 1936).