malformalady:

Living Stones(Dinteranthus vanzylii). Living stones are unusual succulents that have evolved to resemble the pebbles and rocks that litter their native habitats through southern Africa. Structurally, living stones are comprised of two fused leaves above ground that connect to an underground stem with a long root. The leaves are extremely thick and the degree of fusion depends on the species

Photo credit: © Etwin Aslander