Pans
Pans are kind of like the erosional form of a dune, but can also form through abrasion of harder material. They are created when wind erodes away loose surface material and leaves a pan-shaped hollow. The reason that the entire structure isn't eroded away can be explained in a number of ways. Vegetation can lock sediment in place, finer grained material can be easier to entrain, deposition can be happening on the upwind face of the structure at the same time, pans can also form in harder material when entrained windblown sediment scowers away at the surface of the rock etc. The important bit is that pans are created through wind erosion.