A gnarled old Dioscorea hemicrypta caudex has accumulated enough debris in the folds of its surface for a Crassula rupestris plant to grow successfully from it.
Commonly called elephant’s foot, this picture suggests elephant’s eye rather, sporting trendy Crassula shades. No respectable elephant (or crocodile) would allow such developments upon its skin.
The Crassula roots may well receive some nourishment from the thick dry bark of the Dioscorea itself, not only from aggregated dirt.