Sculpt Brush "Basis Mesh"

You know how when you use negative strength in weight painting, it automatically restores that part of the mesh to the original shape? It would be nice to have a sculpt brush that has the same effect, and which ever part is being brushed, returns to the shape of the basis mesh, this would be useful for shapekeys that can't be fixed easily, but a part of the shapekey needs to be closer to the basis mesh shape.