Pseudolithos migiurtinus
Pseudolithos migiurtinus is a species of succulent plant in the genus Pseudolithos. Native to Somalia, it is akin to other species in the genus in that it grows in arid environments and is a small, leafless plant that looks somewhat like a stone, hence the name (Pseudolithos meaning "false stone"). It can range from green to ochre in color. This species is up to  high and  around, can be either cubiform or cylindrical in form, and may grow small branching columns in older plants. References

migiurtinus
Flora of Somalia
Plants described in 1975