Elephant Boy is episode 17 of Mirror Mirror Series 2 and episode 37 overall.
A travelling circus on the goldfields features James, a deformed "elephant boy" - a freak for the audience to ogle. The children decide to help him by bringing him through the mirror for plastic surgery. However, their plan misfires. Modern medicine is not as infallible as they thought, and James has lost the only family that he has ever known.