A dungeon imp presented this riddle to an unknown adventurer when he pressed a black button beside a chasm in Gruntburg:
  1. "A boy was hurt and brought, unconscious, to a hospital. The doctor on duty, Doctor Manson, said 'Oh, my! This is my son!' and proceeded to treat the boy.
  2. "Later, the boy awoke and Nurse Lanolin bustled to his side. It was her first day at the hospital, and she was trying hard to do everything right. She glanced at his medical chart, which included a message from Doctor Manson to 'take good care of my son!' Nurse Lanolin told the boy, 'Your father, Doctor Manson, treated you himself!'  The boy looked puzzled. 'Doctor Manson isn't my father!'
  3. "Assuming that neither the boy nor the doctor is lying, who is Doctor Manson?"

The adventurer provided the correct answer to this riddle, "his mother" and a passage opened to a hidden Meat Closet containing pepperoni.

SOURCE(S): Zork Zero (sample transcript)