malformalady:

Of the many species of stapeliads in cultivation, Caralluma russelliana is the most massive. The four-angled, blue green stems are up to three inches thick and two feet tall. Plants branch freely and form a rather large shrub, creating a sculptural marvel that looks more like a sea creature than a land plant. Tennis ball-sized globes of small reddish-black flowers appear sporadically on stem tips throughout the warm season. Like most stapeliads, the flowers stink of carrion.