Story of Pandasura: Pandasura was a great Shiva Bhakta. After thousands of years of penance, Lord Shiva appeared before him and the demon requested for a peculiar benediction that he should never be killed by anyone and live forever. However, Lord Shiva had a different opinion on the birth and death aspect of humans. He said anyone born on this earth must die one day. Pandasura laid down one condition that he shouldn't be killed by either human or animal or by natural causes. He could be annihilated only by a woman not born of another woman. He also insisted that she should live her life eating faecus as food. Shiva granted this wish to him.
Pandasura, being a great warrior and having attained this special wish, went into the dangerous game of massacre of humans to reign power. When the Devas felt that his torture exceeded the limits, they approached Lord Shiva seeking his intervention to save them from this cruel ruler.But Lord Shiva expressed his inability in this matter since he had given this benediction and asked them to approach the Divine Mother Sri Raja Rajeshwari for a solution. 
When they approached the Goddess, she soothed them with the promise that very soon Pandasura would be destroyed.
She started contemplating as to what kind of incarnation would help her kill Pandasura, since he had been destined to die by unique creation,
that would have to take birth as a woman and not in human body. There was only one possibility for this strange combination. It was to take the incarnation of a boar - a wild pig with tusks with female human body and face of a boar.
However there was a problem as the same incarnation in the form of Varahi had already been taken by Sri Maha Vishnu. (Dasavatharam).
At the behest of Sri Vishnu and keeping his form, deep within, Mother took the form of boar and came to be known as Sri MahaVarahi.
Sri Maha Varahi took with her, son Lord Ganesha, and destroyed Pandasura and established peace.
Worshipping Goddess MahaVarahi is result of Past virtues and good deeds. Chanting Varahi Varahi Varahi three times will bring in endless bliss and euphoria in Life.
