The "Cartoon nail" is the pocket version of the well known "hidden nail under the cup" (Smash and Stab) trick which has many variations.
There are three black envelopes here and each contains a white plastic card. The magician asks the spectator to select one of the white plastic cards and draw a nail on it with the white board marker. The spectator mixing well the envelopes one of them containing the white plastic card with the drawing, the other two contains the empty cards. The magician finds without mistake the envelope which contains the white plastic card with the drawing. There is nothing added or taken away during the presentation, no gimmick at all. No magnet, no electronics, no built-in audience member but a very simple idea. It can be repeated many times. Everything can be examined before and after the presentation. Last but not least this is the safest trick among the “hidden nail under the cup” variations. The trick does not require any sleight of hand or much practicing.