This is an amazing demonstration of "mind over metal", as made famous by Uri Geller.

PKMB or "psycho kinetic metal bending" became a subject of scientific study after Geller's amazing demonstrations in 1972, and in this effect the phenomenon is demonstrated using a solid 1/4" diameter iron nail, some 5" long. The nail is cushioned in a piece of rubber tubing, and held between the performer's fingers. As the performer concentrates, the nail slowly bends in an uncanny fashion, almost to right angles. It is then straightened, removed from the tube and shown to be rigid and solid once again.

With a little flair for presentation, this is a knock out effect, performed right under the spectator's nose.