Who is Magnifico the Clown, otherwise known as the Mule from Foundation and Empire and what is their importance?

Magnifico is taken in by Bayta on a beach on the resort planet Kalgan. Magnifico is running down the beach when he stops to talk to Bayta. Toran thinks it's Bayta's good looks that attracted the clown's attention, but Magnifico will later say that he knew she was from the Foundation. Bayta believes Magnifico will be the link she's searching for to find the Mule and takes him in.