Hermione Granger was shrinking against the wall opposite, looking as if she was about to faint. The troll was advancing on her, knocking the sinks off the walls as it went.

“Confuse it!” Harry said desperately to Ron, and, seizing a tap, he threw it as hard as he could against the wall.

The troll stopped a few feet from Hermione. It lumbered around, blinking stupidly, to see what had made the noise. Its mean little eyes saw Harry. It hesitated, then made for him instead, lifting its club as it went.

“Oy, pea-brain!” yelled Ron from the other side of the chamber, and he threw a metal pipe at it. The troll didn't even seem to notice the pipe hitting its shoulder, but it heard the yell and paused again, turning its ugly snout toward Ron instead, giving Harry time to run around it.

“Come on, run, run!” Harry yelled at Hermione, trying to pull her toward the door, but she couldn't move, she was still flat against the wall, her mouth open with terror.

The shouting and the echoes seemed to be driving the troll berserk. It roared again and started toward Ron, who was nearest and had no way to escape.

Harry then did something that was both very brave and very stupid: He took a great running jump and managed to fasten his arms around the troll's neck from behind. The troll couldn't feel Harry hanging there, but even a troll will notice if you stick a long bit of wood up its nose, and Harry's wand had still been in his hand when he'd jumped - it had gone straight up one of the troll's nostrils.

Howling with pain, the troll twisted and flailed its club, with Harry clinging on for dear life; any second, the troll was going to rip him off or catch him a terrible blow with the club.

Hermione had sunk to the floor in fright; Ron pulled out his own wand — not knowing what he was going to do he heard himself cry the first spell that came into his head: “Wingardium Leviosa!”

The club flew suddenly out of the troll's hand, rose high, high up into the air, turned slowly over — and dropped, with a sickening crack, onto its owner's head. The troll swayed on the spot and then fell flat on its face, with a thud that made the whole room tremble.

Harry got to his feet. He was shaking and out of breath. Ron was standing there with his wand still raised, staring at what he had done.

It was Hermione who spoke first.

“Is it — dead?”

“I don't think so,” said Harry, I think it's just been knocked out.”

He bent down and pulled his wand out of the troll's nose. It was covered in what looked like lumpy gray glue.

“Urgh — troll boogers.”

He wiped it on the troll's trousers.