A New York company called Ecovative Design grew mycelia into a custom drone-shaped chassis you see above. Unfortunately, some parts of the drone just can't be replaced with biodegradable materials for now, though the team tried to stay true to the idea and used silver nanoparticle ink (which can disintegrate along with the chassis) to print the device's circuits. For the test flight earlier this month, the team had to use propellers, controls and batteries taken from an ordinary quadcopter, but that might change in the future. You can read all about the development process on the scientists' website, where you can also download some 3D printable files of a few drone chassis concepts.

Update (November 26, 2014): Lynn Rothschild reached out to us in order to address some comments and clarify a few things. She wrote: