A fierce battle was fought between Shiva and Ganesha. When Lord Shiva realized that Ganesha was dominating the fight, he severed his head with his trishul.
Parvati became extremely furious at the death of Ganesha. Her anger resulted into the manifestation of innumerable goddesses, who started creating havoc on the deities.
The deities became frightened and they were forced to take the refuge of Parvati. They eulogized her and requested to be pardoned. Parvati told them that they could be saved only when Ganesha becomes alive and becomes worshippable just like thee (deities).
The deities went to lord Shiva and requested him to make Ganesha alive once again. Lord Shiva instructed them to go in the northern direction and bring the head of any creature they might find and join it with the trunk of Ganesha. The deities followed the instruction and went in the northern direction.
They found an elephant which had only one tusk. They severed the elephant’s head and joined it with the trunk of Ganesha. By the blessings of Shiva, Ganesha became alive once again. The deities worshipped Ganesha and returned back to their respective abodes.