The Loft command is fascinating for the fantastical shapes it creates. It takes two or more 2D objects (like circles or ellipses at different elevations) or the faces of 3D solids, and then creates a solid that smoothly transitions between them.
This video shows you how to use the Loft command between three ellipses, and then between two 3D solids. It shows the surprising effects you can achieve with lofts when you change the settings between ruled, smooth, normal, and draft-angle values.
Join 2D and 3D shapes with a solid using the Loft command