The next day, the same performance, with the man walking out laughing,
     fit to bust. The pharmacist thinks this odd and asks his assistant, if
     the man returns, to follow him.

     Sure enough, he comes into the store the next day, repeating his
     actions once more. The assistant duly follows. Half an hour later, he
     returns.

     "So did you follow him?"

     "I did."

     "And...where did he go?"

     "Over to your house..."