What is it??? Dead things, hairy things, fake dead things with fake worms? Ew. It sure smells like dead things.
This is Stapelia gigantea, with flowers easily 10 inches across and up to 12 inches across. The buds take weeks to develop. By the time they're the size of a small lemon you think, "It's sure to open soon!" But alas, it will still have several weeks to go. They pop (litterally) open when they get to about the size of an average orange. Then they proceed to stink and attract flies.
Most people will grow these in well drained soil, but ever the oddball, my approach is to grow it in sphagnum moss, allowing it to dry out completely between watering. Obviously, you can't keep it in constantly wet sphagnum, but regular wet/dry cycles works out just fine. They'll want bright light to full sun, such as the conditions in which you might grow Cattleyas. This beastie was grown from a cutting rooted about a year ago, and during that time it has doubled in size (and weight! heavy plant). They're easy to grow and very interesting to look at. Certainly a plant worth having, just don't put it on the dining room table when you have guests.