Answer: A common riddle answer is a shadow — as you get closer to the light source, the shadow often gets smaller. Another likely answer is an object in perspective : it only looks smaller because of distance and viewing angle, not because it actually shrinks.

Why this fits

  • In everyday visual perspective, things can appear smaller as the distance or camera framing changes, even when their real size stays the same.
  • That’s why the line is often used as a riddle: it sounds physical, but the trick is usually about how we see things.

Other possible riddle answers

  • A shadow.
  • A piece of soap as it gets used up over time.
  • A bladder in a joking riddle context, though that’s not the usual answer.

Simple version

If you meant the classic puzzle, the best single answer is: a shadow.