We all know that Voldemort lived in an orphanage somewhere in London. So suppose it was near RAF Biggin Hill, which was attacked in August 1940, while Voldemort was there for the summer holidays (let's say it was not evacuated since it's not in central London). So Voldemort was rushed to a nearby air-raid shelter (or basement) and had to sit there for the longest hour of his life while the airfield was raided by Ju-87 divebombers. What particularly stuck with him was the sound, that infernal wailing of the Jericho trumpets affixed to the landing gear of the Stukas followed by the explosions of their bombs.
What few people know, the Jericho trumpets were inspired by the cry of a Veela, the avian apex predator of Eastern Europe.
The battle for Hogwarts is going well for Voldemort , until a spell hits Fleur and throws her against a wall. Howling in pain, she snaps and transforms, letting out an ear-piercing, soul-rending screech. A screech which leaves the Dark Lord frozen in fear