So, Quasimodo has been ringing the bell at Notre Dame for years, and wants a vacation. He asks the Sexton for a week off.
The Sexton says yes, but asks Quasimodo to select and train a temp to do the job while Quasimodo is on vacation. He selects his twin brother, who has no arms. The brother learns to ring the bell by running into it with his face. Painful, but effective.
His second day on the job he misses the bell and falls to his death on the plaza below. Two witnesses run up. One asks “Who is he?”
“I don’t know his name, but his face rings a bell” replies the first.
“Now that you mention it, he’s a dead ringer for his brother” says the second.