Kapotakandara
Kapotakandara：A grotto，probably near Rājagaha，where，later，a vihāra，called 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 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．39f； Thag．vs．998f； PsA．494）．
According to the Visuddhi-magga （p．380），Sāriputta entered into a trance at the very moment the blow was dealt him．