Professor Sprout headed off into the gathering darkness in the direction of her greenhouses, and Slughorn directed his steps to the spot where Harry stood, invisible.
Seized with an immediate desire to reveal himself, Harry pulled off the cloak with a flourish.
“Good evening, Professor.”
“Merlin’s beard, Harry, you made me jump,” said Slughorn, stopping dead in his tracks and looking wary. “How did you get out of the castle?”
“I think Filch must’ve forgotten to lock the doors,” said Harry cheerfully, and was delighted to see Slughorn scowl.
“I’ll be reporting that man, he’s more concerned about litter than proper security if you ask me… But why are you out then, Harry?”
“Well, sir, it’s Hagrid,” said Harry, who knew that the right thing to do just now was to tell the truth. “He’s pretty upset… But you won’t tell anyone, Professor? I don’t want trouble for him…”
Slughorn’s curiosity was evidently aroused. “Well, I can’t promise that,” he said gruffly. “But I know that Dumbledore trusts Hagrid to the hilt, so I’m sure he can’t be up to anything very dreadful…”
“Well, it’s this giant spider, he’s had it for years… It lived in the forest… It could talk and everything—”
“I heard rumors there were Acromantula in the forest,” said Slughorn softly, looking over at the mass of black trees. “It’s true, then?”
“Yes,” said Harry. “But this one, Aragog, the first one Hagrid ever got, it died last night. He’s devastated. He wants company while he buries it and I said I’d go.”
“Touching, touching,” said Slughorn absentmindedly, his large droopy eyes fixed upon the distant lights of Hagrid’s cabin. “But Acromantula venom is very valuable… If the beast only just died it might not yet have dried out… Of course, I wouldn’t want to do anything insensitive if Hagrid is upset… but if there was any way to procure some… I mean, it’s almost impossible to get venom from an Acromantula while its alive…”
Slughorn seemed to be talking more to himself than Harry now.
“…seems an awful waste not to collect it… might get a hundred Galleons a pint… To be frank, my salary is not large…”
And now Harry saw clearly what was to be done.
“Well,” he said, with a most convincing hesitancy, “well, if you wanted to come, Professor, Hagrid would probably be really pleased… Give Aragog a better send-off, you know…”
“Yes, of course,” said Slughorn, his eyes now gleaming with enthusiasm. “I tell you what, Harry, I’ll meet you down there with a bottle or two… We’ll drink the poor beast’s—well—not health—but we’ll send it off in style, anyway, once it’s buried. And I’ll change my tie, this one is a little exuberant for the occasion…”