 Much of the episode 's plot revolves around a practical joke with a fake cake that Jim has set up in an attempt to fool Pat . Moving the cake reveals the head of the person hiding under the table , but , in the mean time , the hidden character can hear conversations taking place nearby , unbeknownst to those who are not in on the joke . The episode plays on viewers ' guesses as to what has led to the arrival — seen at the opening of the episode — of a paramedic . In particular , the person under the table is at risk of injury if candles burn down or someone puts a knife into the " cake " . 
