Widening Gyre

Nick Tabor calls Yeats' “The Second Coming” the "most thoroughly pillaged piece of literature in English":

Since Chinua Achebe cribbed Yeats’s lines for Things Fall Apart in 1958 and Joan Didion for Slouching Towards Bethlehem a decade later, dozens if not hundreds of others have followed suit, in mediums ranging from CD-ROM games to heavy-metal albums to pornography. These references have created a feedback loop, leading ever more writers to draw from the poem for inspiration.

He has a theory as to why the poem is so pillagable:

Yeats’s lines work outside their context because the word pairings are brilliant in and of themselves. “Blank and pitiless as the sun,” “stony sleep,” “vexed to nightmare by a rocking cradle”—they’re both jarring and sonorous. Even “slouching towards,” probably the most overused phrase of them all, retains its ominousness after all this repetition. We’d expect the rough beast to “plod,” like a limping monster in a horror movie or the killer in No Country for Old Men (which itself, of course, takes its title from another of Yeats’s lines, in “Sailing to Byzantium”). But plodding is a conscious action; slouching is not. We can’t even tell whether the beast has a will of its own. The verb heightens the mystery and dread.