From Controllable Third Thumb lets wearers extend their natural abilities

For her graduate work at the Royal College of Art, Dani Clode created a wearable third thumb that can help its user carry more objects, squeeze lemons or play complex chords on the guitar.

The Third Thumb is a motorised, controllable extra digit, designed for anyone who wants to extend their natural abilities.

Dezeen has some great photos and videos of this.