Hermione smiled but made a “shhing” gesture, so that they could hear what Slughorn was saying. Ron looked slightly disgruntled.
“Amortentia doesn’t really create love, of course. It is impossible to manufacture or imitate love. No, this will simply cause a powerful infatuation or obsession. It is probably the most dangerous and powerful potion in this room—oh yes,” he said, nodding gravely at Malfoy and Nott, both of whom were smirking skeptically. “When you have seen as much of life as I have, you will not underestimate the power of obsessive love…
“And now,” said Slughorn, “it is time for us to start work.”
“Sir, you haven’t told us what’s in this one,” said Ernie Macmillan, pointing at a small black cauldron standing on Slughorn’s desk. The potion within was splashing about merrily; it was the color of molten gold, and large drops were leaping like goldfish above the surface, though not a particle had spilled.
“Oho,” said Slughorn again. Harry was sure that Slughorn had not forgotten the potion at all, but had waited to be asked for dramatic effect. “Yes. That. Well, that one, ladies and gentlemen, is a most curious little potion called Felix Felicis. I take it,” he turned, smiling, to look at Hermione, who had let out an audible gasp, “that you know what Felix Felicis does, Miss Granger?”
“It’s liquid luck,” said Hermione excitedly. “It makes you lucky!”
The whole class seemed to sit up a little straighter. Now all Harry could see of Malfoy was the back of his sleek blond head, because he was at last giving Slughorn his full and undivided attention.
“Quite right, take another ten points for Gryffindor. Yes, it’s a funny little potion, Felix Felicis,” said Slughorn. “Desperately tricky to make, and disastrous to get wrong. However, if brewed correctly, as this has been, you will find that all your endeavors tend to succeed… at least until the effects wear off.”
“Why don’t people drink it all the time, sir?” said Terry Boot eagerly.
“Because if taken in excess, it causes giddiness, recklessness, and dangerous overconfidence,” said Slughorn. “Too much of a good thing, you know… highly toxic in large quantities. But taken sparingly, and very occasionally…”
“Have you ever taken it, sir?” asked Michael Corner with great interest.
“Twice in my life,” said Slughorn. “Once when I was twenty-four, once when I was fifty-seven. Two tablespoonfuls taken with breakfast. Two perfect days.”
He gazed dreamily into the distance. Whether he was playacting or not, thought Harry, the effect was good.
“And that,” said Slughorn, apparently coming back to earth, “is what I shall be offering as a prize in this lesson.”