Rubberwood

Rubberwood is a original material.

A stretchy, rubbery wood (hence it's name), while it's quite sturdy, should you make a aperture (say, a door) with it, anything bigger than the aperture will be able to fit through without difficulty.

Rubberwood has a rubbery color.

There is a stronger variant, Ironwood, too.

Ironwood
Ironwood is stronger than Rubberwood, yet just as stretchy and flexible.

It has a gray, metallic color.