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Evidently Snape had noticed them talking and whirled to face Harry. "Another five from Gryffindor for talking during class. Perhaps, since you aren't paying attention, you feel you already know the lesson? Describe for me the properties of a poison."

Harry smirked nastily at the Professor while the rest of the class watched in silence. Perhaps, Harry thought, the original version of me would back down from his greasiness, but not this time! Hermione was hissing at him to drop it, but he ignored her. While Harry would never forget his Snape's sacrifice, it was time to have a bit of fun. He pulled on a bit of his Auror training to answer. "A poison is any substance that affects the human body in a negative way. Like the oil in your hair."

There was a shocked gasp in the classroom but more than a few snickers and giggles. Snape looked murderous. "Ten points from Gryffindor for your cheek, Potter!" he snarled. Then he fired another question. "You have a black substance in a vial. It is thick and viscous, and smells of ink. Identify."

Harry was tempted to answer "Ink?" but bit his tongue, knowing that Snape would just throw a hissy-fit at him. "Black death." he said with certainty. "Causes blindness followed by insanity. Needs to be ingested, which is hard since it has a distinct smell, or administered in a wound or intravenously. There is no known cure."

A vein throbbed in Snape's forehead and he began to list more and increasingly rare poisons that Harry countered effortlessly with the explanation and antidote if there was one. Finally, Snape snarled, "And just how would one such as you know about so many poisons, Potter?"

Harry could hear Hermione nearly begging him not to continue under her breath, but he ignored her. Vengeance was sweet. "Because, Snivellus. I'm planning on poisoning you at some point this year."

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