"Porphyria's Lover" by Robert Browning starts off as a standard Victorian romantic poem about a man waiting in a cold, "cheerless" cottage for his lover Porphyria to arrive. She comes in out of the driving rain, kindles a fire, and pledges her love for the narrator. Then we get this:
"...That moment she was mine, mine, fair,/Perfectly pure and good: I found/A thing to do,and all her hair/In one long yellow string I wound/Three times her little throat around,/And strangled her..."
By the same poet (Edwin Arlington Robinson), we get the poem of Miniver Cheevey, who wishes he'd lived in the time of knightly chivalry. The last verse goes: "Miniver Cheevey, born too late/Scratched his head and kept on thinking/Miniver coughed and called it fate/And kept on drinking."
In "Ozymandias" by Percy Bysshe Shelley, the statement of the great king and the revelation after comprise the Wham Phrase.