Merlins of Wakefield - It's always magic at Merlins

The magician shows a large nasty looking chefs knife. The knife can be shown from all angles, there is nothing untoward to see. Suddenly the magician slices deep into his arm. Blood oozes out from the wound,and every thing can be viewed from all around! The knife is remove and the blood wiped away to show a completely unharmed arm. This can even be done on a spectators arm. Not to be confused with inferior versions, This is the best available