Gulliver's Travels Part 3 Chapter 10

In which the narrator encounters the Luggnaggians, a courteous and proud people, and learns of the rare struldbrugs—mortals born with the dreadful gift of immortality marked by a changing spot on their foreheads. After hearing his eloquent praises of endless life, he is gently corrected and informed of the melancholy, decay, and societal exile that burden these immortals, leading him to a profound reconsideration of the desirability of perpetual existence.