Aghasura

In the Bhagavata Purana narrative cycle of Kṛṣṇa’s childhood pastimes (līlā), Aghasura appears as an asura allied to the tyrant Kamsa and is presented as brother to hostile beings such as Putana and Bakasura. Sent by Kamsa to slay the child Kṛṣṇa after his siblings had been killed, Aghasura takes action during a pastoral picnic in the forests of Vṛndāvana: he conceals himself against a mountain, presenting his enormous open mouth as a cave so that the cowherd boys and their calves will enter and be suffocated.

Narrative and pictorial sources describe Aghasura as manifesting in the form of a vast, cavernous serpent whose open maw is indistinguishable from a mountain cavern. Artistic depictions (for example, a Pahari/Garhwal painting cited in museum documentation) show a giant snake with an enormous open mouth into which the boys and Kṛṣṇa enter. Sources emphasize scale and a gaping, cave-like mouth rather than fine anatomical detail; one modern summary (Wikipedia) cites an "8-mile-long" figure, while primary narrative descriptions use terms meaning enormous or vast.

In the canonical story Aghasura’s principal tactic is disguise and ambush: he assumed serpent form and positioned his open mouth as a fatal trap, intending to suffocate the cowherd boys. The episode depicts a contest of expansion when Kṛṣṇa enters the serpent; Kṛṣṇa enlarged his form faster, causing Aghasura to suffocate internally, his life‑force to be unable to escape, and finally to burst out through the demon’s head, resulting in Aghasura’s death. The account frames these abilities as episodic: the shape assumed (serpent) and the ambush by suffocation are the demonstrated behaviors in the text.