The Story of Bhasmasur

Bhasmasura was an Asura-devotee of God Shiva. He performed great penance to obtain a boon from the deity. Shiva granted him the power to burn and turn into ashes (bhasma) any one on whose head Bhasmasura was to place his hands. But Bhasmasura thereupon attempted to touch the head of Shiva with his hand in desire to possess Parvati after Shiva. Shiva fled to seek Vishnu's help.

Vishnu, in the form of Mohini, appeared in front of Bhasmasura. Mohini enticed Bhasmasura with her beauty. Bhasmasura asked Mohini to marry him. Later agreed on the condition only if Bhasmasura could match her moves identically. The dance contest went on for days and he began to let his guard down. While still dancing, Mohini, struck a pose where her hand was placed on top of her own head. As Bhasmasura imitated her, he immediately burned and turned into ashes. 
This story, like many others from the scriptures, highlight upon the fact that great boons are no good when applied for derogatory personal goals!