What is ‘Mohini Ekadasi’?

In Rukmangada Charitra, once a Mohini tried to entice Rukmangada. When the Mohini was relieved of her sins (‘shapa vimochana’), she requested that on those Ekadsai days, which have ‘puchcham’ (extension to the next day as a residue), a portion of the ‘phala’ (merits) be granted to her. Hence such and Ekadasi is called ‘Mohini Ekadasi’.