This houseplant appears to be what I would call a succulent - by which
I mean the leaves are slightly fat and juicy.

They are dark green and rather curly. No flowers. It doesn't appear
to like a lot of water. The leaves grow in a rather curlicue way -
picture corkscrew curls, and you'll have a good idea.

I want to find out what kind of plant this is before I kill it!