Bumpy Octahedron is folded from a single sheet of 2:1 paper. Each face is decorated with a sunken triangular pyramid which looks similar to a PVM unit.
Foil paper is recommended since there are no tabs to close the model - it is open at the back, just two paper edges which with perfectly thin and stiff paper would just touch. In the real world they do not, and the shape takes a Pacman-like appearance (I gotta fold it in yellow paper some time). Foil paper makes it possible to keep the split relatively small.
A Precrese Pattern (PreCP) is available for this model: