S3E8 · The One With the Giant Poking Device

Complete story — includes the ending

When Chandler wants to buy Janice an expensive gift for her birthday, Joey reveals that he saw her kissing her ex-husband. Upon confronting her about the kiss and heeding Joey's advice, Chandler reluctantly breaks up with her, not wanting her to destroy her family. While babysitting Ben, Monica accidentally bumps his head on a post. Both Monica and Rachel try to hide the bump from Ross, though Ross manages to guilt trip his sister and ultimately bumps his head afterwards, also on a post and seemingly on the same spot as his son. Phoebe has a bad toothache but fears going to the dentist because it always leads to somebody that she knows dying. She finally visits the dentist after Rachel urges her to, and upon returning, is relieved to find out that everybody she knows is still alive, thereby "breaking the curse". However, her happiness is short-lived when the gang notices shortly afterwards that Ugly Naked Guy has been lying motionless in his apartment in the adjacent building for the entire day. The gang then fashions a long and giant poking device using only chopsticks to determine if he is alive and is relieved when he swats it away.