I could a tale unfold whose lightest word
Would harrow up thy soul, freeze thy young blood,
Make thy two eyes, like stars, start from their spheres,
Thy knotted and combined locks to part
And each particular hair to stand on end,
Like quills upon the fretful porpentine:
But this eternal blazon must not be
To ears of flesh and blood.
P.G. Wodehouse used the part about the "fretful porpentine," that is, porcupine, at least three times in his work. Amazing that Wodehouse made such terrific jokes (take my word for it) out of such a harrowing passage from Shakespeare. The lines are from Hamlet's father's ghost, and he is describing what he can't say about hell.
I thought of these lines during a debate on another blog, where a commenter made a series of rather jumbled remarks a la Bertie Wooster in three of Wodehouse's novels, and gave a serious subject a silly turn.
Here is a great parody of Wodehouse that demonstrates the "fretful porpentine" thing.