What is a Multi-Plane?

A woodworker on one of the forums discovers a Record Multi-plane and falls in love. What is it and how do you use it?

Michael Dresdner: A multiplane is an all-in-one molding plane that will cut a variety of shapes and types of grooves with its large variety of cutters and settings. You use it just like any other plane, only it cuts shapes instead of flats.