Boyle's diction in "Greasy Lake" is intense, elevated, and original all the way through the story, contrasting sharply with the subject matter. You could pick almost anywhere in this text to give an interesting example of descriptive/original language. I've included a few here from the opening of the text.
In the opening description of the lake, Boyle writes "there was a single ravaged island a hundred yards from shore, so stripped of vegetation it looked as though the air force had strafed it" (Boyle, 688). This sentence essentially says that there was an island in the lake with no plant life on it, however, Boyle describes it as "stripped of vegetation," "ravaged," and "strafed". This language is pretty academic for its subject matter, and the word "strafed" itself is reasonably uncommon and specific. If something has been "strafed" it has been attacked repeatedly from close range, and usually it refers to repeated bombing or gunfire from low-flying aircraft. This one word reveals a lot about the condition of the island and about Boyle's writing style.
In the same paragraph the narrator says that he and the other characters frequently went up to the lake because "we wanted to snuff the rich scent of possibility on the breeze, watch a girl take off her clothes and plunge into the festering murk . . . savor the incongruous full-throated roar of rock and roll against the primeval susurrus of frogs and crickets" (Boyle, 688). Again Boyle's language is specific and original. He uses some uncommon words like "snuff," and "incongruous." He also uses the word "festering" to describe the lake, implying that not only is the lake dirty, but that it is actively rotting or decomposing. Finally, he describes the natural sounds of the lake as the "primeval susurrus." This particular unusual phrase describes the lake noise as a whispering or murmuring (susurrus) that comes from the earliest instincts or history of the world.