Lettuce Bush plus A Mystery

Here’s the result of several lettuce
seeds sharing a large pot.

Does anyone know what this succulent is?
I did not plant it.  But several years ago
(after living here for over a decade) it
gradually popped up and stayed here.
I have taken some cuttings to spread
it around our property.  For now we’ve
been calling it our alien plant.  If you
recognize it, please let me know.
Have a wonderful day, everyone!