A grotto, probably near Rājagaha, where, later the Kapotakondara-vihāra, was built. The grotto was at one time the residence of a large number of pigeons (kapotā), hence the name (UdA.244). On one occasion Sāriputta, having recently shaved his head, was seated there wrapt in concentration (samādhi), and a yakkha, passing overhead with his friend to an assembly of yakkhas, yielded, despite the warning of his friend, to the temptation to give a knock on the monk’s shining head. The yakkha immediately fell down and was swallowed up in the fires of hell. Sāriputta had but a slight headache after the blow, which was, it is said, heavy enough to crush an elephant (Ud.39 f; Thag.vs.998 f; PsA.494).
According to the Visuddhimagga (p.380), Sāriputta entered into absorption at the very moment the blow was dealt him.