Check this out:
This is a cutting of an extra-succulent pink-flowering Thanksgiving cactus. Normally segments are flat, but this one has three ends, with part of a fourth on the bottom (which may not be very visible, in the picture, if visible at all).
See this similar post about a Christmas cactus:
I used to think this Thanksgiving cactus was a Christmas cactus, but nope. It's either a Thanksgiving cactus or a hybrid with one. It does flower at Christmas, though (and no, I didn't get it from a store).