His taut posture is the active warrior pose (pratayalidha), based on an archer's stance but resembling the en garde position in Western fencing. His outstretched right hand brandishes a vajra and his left hand deftly holds a lasso - with which he binds demons. He wears a skull crown with his hair standing on end. His expression is wrathful and he has a third eye. Around his neck is a serpent necklace and his loin cloth is made up of the skin of a tiger, whose head can be see on his right knee.
Vajrapani is believed to be the savior of snakes (nagas), and since the Nagas are believed to control the rain-clouds, Vajrapani as their protector is looked upon as the Rain God, and it is to him Buddhists appeal when rain is needed, or is too abundant. In this capacity Vajrapani is identified with Indra, the Indian god of Rain.
This description by Nitin Kumar, Executive Editor, Exotic India.