Vyomasura

In the devotional-narrative corpus (notably the Srimad Bhāgavatam and its retellings), Vyomasura is named as a son of Mayasura and appears during Krishna's childhood pastimes. He joins the cowherd boys during play, disguised as one of them, and uses that cover to abduct those playing the roles of goats and other creatures, carrying them to mountain caves. The episode functions within the Bhagavata devotional frame as one of several childhood confrontations between Krishna and hostile asuras. (Sources: Srimad Bhāgavatam Canto 10; Vedabase commentary; multiple retellings.)

Narrative accounts describe Vyomasura taking the form of a youth in order to impersonate a cowherd boy and join their game; sources also call him an asura and 'magically-gifted.' Specific, consistent physical details of a true, unmasked form are not given in the supplied sources beyond his identification as the son of Mayasura and his capacity for disguise. Some modern retellings render him with epithets such as 'the demon in the sky' (reflecting an interpretation of the name vyoma), but primary narrative excerpts do not provide a formal etymological gloss. (Sources: Srimad Bhāgavatam episode summaries; ISKCON/Hare Kṛṣṇa retellings; Wikipedia summary.)

Sources portray Vyomasura as magically skilled in disguise (able to assume the appearance of a cowherd youth) and capable of abducting and enclosing many boys by carrying them to mountain caves and shutting them within; retellings speak of him 'sealing the mouths of the caves' or 'shutting the boys within.' He is not invulnerable to divine force: Krishna overtakes, captures, and kills him and breaks the cave seals to free the boys. Vyomasura's parentage (son of Mayasura) situates him in a lineage associated with magical craftsmanship and shapeshifting in other narratives. (Sources: Srimad Bhāgavatam Canto 10 / Vedabase; ISKCON/retellings; Wikipedia.)