The married Blodeuwedd has an affair with Gronw Pebyr of Penllyn, and the lovers decide to kill Lleu. Like Delilah in the Bible and other femmes fatales, Blodeuwedd talks her husband into revealing the fact that he can never be killed in a house, on a horse, or on foot outdoors. In fact, he can only be killed only by a special spear. One day when Lleu is taking a bath, he is tricked into standing with one foot on the tub and the other on a goat, a position which negates the restrictions on his death and makes him vulnerable to Gronw’s special sword. In death he soars off as an eagle, but Gwydion finds him and brings him back to human life. Lleu then returns, kills Gronw, and his guilty wife is turned into an owl.
The lovers Blodeuwedd and Gronw are lovers in a Celtic myth about the murder of Lleu, Blodewedd’s husband. As with the story of Samson and Delilah, the murder must be conducted using trickery.