"So Jesus asked, 'What is your name?' And he replied, 'Legion, because we are many.' And they begged Jesus not to order them to go back into the Abyss. Instead, the demons asked Him to be allowed to go into a large herd of swine that were feeding there on the hillside. When the demons came out of the man, they went into the pigs, and in their madness rushed down the steep bank into the lake and were drowned." 
Luke 8:30-33