The spectator selects a card, remembers it and places it out of view. A second spectator also selects a card and remembers it. With your hands in FULL view, the first spectator takes any lighter. You could use a candle or anything with a flame! Now pinch your thumb and finger together in the flame whilst the spectator thinks of their card.
A BLISTER appears on your thumb and finger in the shape of THEIR chosen card!
You can also give the spectator the Sharpie to draw the shape of their card on a piece of paper. They fold the paper into four and set fire to it. Placing your finger and thumb into the flames, the blister appears on your thumb and finger in the shape of their card!
You now show the word "Sharpie" printed on both sides of the marker they have just used. You ask the second spectator to think of their card. Take your fingers and rub them over the Sharpie writing. Visually, the name "Sharpie" smudges into the name of their chosen card!
(The writing doesn't have tro smudge, it can simply change into the name of their chosen card in an instant. The choice is yours!).