Has anyone else read Mr Pye, a short novel by Mervyn Peake (better known for his phantasmagorical Gormenghast trilogy)?
The eponymous protagonist, arriving in the Channel Islands, appears to be somewhat of the evangelist sort, and truly does nothing but go about doing good... so much pure goodness, in fact, that one morning he notices two wings starting to sprout from his shoulderblades! Rather disconcerted by this incipient metamorphosis - altogether unsettling, and too much of a good thing - he decides the obvious solution is to do just a few not-so-good deeds; sure enough, the wings wither, but (you guessed it) pretty soon he has the opposite problem of two horns beginning to emerge from his forehead. He alternates more and more rapidly between the two developments, until finally he gives in and... departs for parts unknown, borne upon two magnificent wings.
I think it's a lovely parable of the Christian life, and an amusing little book. We live as if this were the only world, whereas it is but the anteroom.