The whistle echoed shrilly in the cold, still air; the stands erupted with cheers and applause; without looking to see what the other champions were doing, Harry pulled off his shoes and socks, pulled the handful of gillyweed out of his pocket, stuffed it into his mouth, and waded out into the lake.

It was so cold he felt the skin on his legs searing as though this were fire, not icy water. His sodden robes weighed him down as he walked in deeper; now the water was over his knees, and his rapidly numbing feet were slipping over silt and flat, slimy stones. He was chewing the gillyweed as hard and fast as he could; it felt unpleasantly slimy and rubbery, like octopus tentacles. Waist-deep in the freezing water he stopped, swallowed, and waited for something to happen.

He could hear laughter in the crowd and knew he must look stupid, walking into the lake without showing any sign of magical power. The part of him that was still dry was covered in goose pimples; half immersed in the icy water, a cruel breeze lifting his hair, Harry started to shiver violently. He avoided looking at the stands; the laughter was becoming louder, and there were catcalls and jeering from the Slytherins . . .

Then, quite suddenly, Harry felt as though an invisible pillow had been pressed over his mouth and nose. He tried to draw breath, but it made his head spin; his lungs were empty, and he suddenly felt a piercing pain on either side of his neck—

Harry clapped his hands around his throat and felt two large slits just below his ears, flapping in the cold air . . . He had gills. Without pausing to think, he did the only thing that made sense—he flung himself forward into the water.

The first gulp of icy lake water felt like the breath of life. His head had stopped spinning; he took another great gulp of water and felt it pass smoothly through his gills, sending oxygen back to his brain. He stretched out his hands in front of him and stared at them. They looked green and ghostly under the water, and they had become webbed. He twisted around and looked at his bare feet—they had become elongated and the toes were webbed too: It looked as though he had sprouted flippers.

The water didn’t feel icy anymore either . . . on the contrary, he felt pleasantly cool and very light . . . Harry struck out once more, marveling at how far and fast his flipper-like feet propelled him through the water, and noticing how clearly he could see, and how he no longer seemed to need to blink. He had soon swum so far into the lake that he could no longer see the bottom. He flipped over and dived into its depths.