Single stem Large round draping leaves?
Large plant with Large round draping leaves
Hi Carolyn, this is an odd looking thing, for sure - but it's quite pretty.
I'm wondering if it could be Kalanchoe thyrsiflora, also known as the Flapjack plant - there seem to be several different forms, some with more 'bloom' on them than others, and some with rounded rather than heart shaped leaves.
There is also another closely related species, Kalanchoe luciae, which is sometimes called Flapjacks or Paddle Plant as well.
They are also called Desert Cabbage; it's easy to see why!
Have a look on this page to see if any of those look close: Kalanchoe thyrsiflora - scroll down to the bottom and look through other visitors submissions.
Best of luck with your graceful alien plant!