A dad walks into a mall followed by his ten-year-old son. The kid is spinning a 25-cent piece in the air and catching it between his teeth. As they walk through the market someone bumps into the boy at just the wrong moment and the coin goes straight into his mouth and lodges in his throat. He immediately starts choking and going blue in the face and Dad starts panicking, shouting and screaming for help.
A middle-aged, nondescript man in a gray suit is sitting at a coffee bar in the mall reading his newspaper and sipping a cup of coffee. At the sound of the commotion, he looks up, puts his coffee cup down on the saucer, neatly folds his newspaper and places it on the counter. Then he gets up from his seat and makes his unhurried way across the market.
Reaching the boy, the man carefully takes hold of the kid's testicles and squeezes gently but firmly. After a few seconds the boy convulses violently and coughs up the 25-cent piece, which the man catches in his free hand. Releasing the boy, the man hands the coin to the father and walks back to his seat in the coffee bar without saying a word.
As soon as he is sure that his son has suffered no lasting ill effects, the father rushes over to the man and starts effusively thanking him saying "I've never seen anybody do anything like that before - it was fantastic. Are you a doctor?"
"Oh, good heavens, no", the man replies, "I work for the Internal Revenue Service."