beneath Diggory, who was streaking in the opposite direction.... 

There was another clap of thunder, followed immediately by forked lightning. This was getting more and more dangerous. Harry needed to get the Snitch quickly - 

He turned, intending to head back toward the middle of the field, but at that moment, another flash of lightning illuminated the stands, and Harry saw something that distracted him completely , the silhouette of an enormous shaggy black dog, clearly imprinted against the sky, motionless in the topmost, empty row of seats. 

Harry's numb hands slipped on the broom handle and his Nimbus dropped a few feet. Shaking his sodden bangs out of his eyes, he squinted back into the stands. The dog had vanished.

 "Harry!" came Wood's anguished yell from the Gryffindor goal posts. "Harry, behind you!" 

Harry looked wildly around. Cedric Diggory was pelting up the field, and a tiny speck of gold was shimmering in the rain-filled air between them - 

With a jolt of panic, Harry threw himself flat to the broornhandle and zoomed toward the Snitch.

 "Come on!" he growled at his Nimbus as the rain whipped his face. "Faster!" 

But something odd was happening. An eerie silence was falling across the stadium. The wind, though as strong as ever, was forgetting to roar. It was as though someone had turned off the sound, as though Harry had gone suddenly deaf -- what was going on? 

And then a horribly familiar wave of cold swept over him, inside him, just as he became aware of something moving on the field below...

 Before he'd had time to think, Harry had taken his eyes off the Snitch and looked down.