Some succulents are apparently easy to hybridize, and lots of strange freak plants are produced for the pet trade. When I bought this tube-wormy, translucent plant I had no idea what it was, and it doesn't seem to resemble any of the naturally occurring species very closely.
Dr. Internets tells me that this little guy will grow up to a small "tree succulent" with woody stems and clusters of finger-like leaves at the ends, looking remarkably like the whole plant looks now (e.g. this photo). Wonder how long that will take?
If I had known it was a cultivated hybrid instead of a "real plant" I think I wouldn't have bought it. Am I becoming a succulent snob? In spite of its decidedly non-deserty appearance, it seems to do just as well with long dry periods as my other pets.