I've heard of finding the one lost sheep, but this is taking it a little far.  Mark chose to chuck a piece of candy, hoping it would land on top of the fridge.  When it landed then slid BEHIND the fridge, this is what followed...

That's my sister, Jamie, directing him towards the candy.

After about 30 minutes he finally got it.  Good job, Mark!  Using those gastrointestinal scopes at work is paying off at home too!