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It's Mr. McGreg, with a leg for an arm and an arm for a leg!
―Dr. Nick Riviera

Mr. McGreg is a man who once went to the Springfield General Hospital for an unexpected surgery by Dr. Nick Riviera.


He is one of Dr. Nick's patients. After Dr. Nick finishes doing the triple bypass surgery on Homer and telling the rest of the Simpsons that it went successful, he leaves, and is stopped by Mr. McGreg, who is angry and furious for having his right leg be a right arm, and his right arm be a right leg.

Dr. Nick, in typical "Nick Riviera-fashion", simply ignores Mr. McGreg's anger after Mr. McGreg asks if he remembers him, and happily says, "Well, if it isn't my old friend, Mr. McGreg! With a leg for an arm, and an arm for a leg!"