Sentence:  "Take the <WSD>black pill</WSD>," I said. "You once told me I'd never do it. Neither will you. You've got a hollow tooth, I found it when I gagged you. Bite it, take the <WSD>black pill</WSD>. It's easier than drowning." 
Meaning of the word marked with <WSD> tags:  A poison pill; a pill intended to kill the person who ingests it.