Late one night, as a tabby cat with square markings around its eyes stared at the end of Privet Drive, a man appeared-- Appeared so quickly and suddenly that you might have thought he just popped out of the ground. In doing so, he displaced an equal volume of air. This volume of air was shoved outwards at great velocity. This caused the air immediately outside this volume to become compressed, which naturally made it hot. The compression was in fact so great, that the temperature reached into the millions of Kelvins. Therefore, the man who so quickly and suddenly appeared there was instantly vapourised. POOF! He was gone.
But his legacy lived on: The air he displaced was shoved with so much force that it pushed other air molecules out of the way, causing them to compress and heat up, which caused even more air molecules to do the same thing. The heating of the air caused it to expand, pushing still more molecules. This is more generally known as a shock wave. But this didn't frighten the tabby cat, because air that is heated into the millions of Kelvins also releases radiation. The shock wave released so much radiation that the tabby cat was vapourised before the sight of the man or the shock wave had time to register in her brain. The markings around her eyes were also vapourised.
There was a family of three inside the house in front of which the cat had been standing. This family was of the most unpleasant lot in England, and they would not have been happy to know that a strangely-dressed man had intended to leave them with an odd baby. They would have been happy to know that this man had just accidentally vapourised himself. The house itself reflected most of the radiation away, protecting the family from instant vapourisation, and for a while it seemed that they would be alright. That "while" lasted approximately 2.5 microseconds. They were left alive only to face a shock wave that was advancing at a supersonic velocity. They were fried by the heat of the compressed air, and then smashed to bits.
Meanwhile, a large man on an enormous flying motorbike was bringing a baby with a lightning-bolt-shaped cut on his forehead to a location specified by his boss, Albus Dumbledore. He saw a brilliant blue light directly ahead, and could just make out a mushroom cloud before he went blind. This explosion was releasing an amount of radiation appropriate for a white dwarf. The man, and the baby he was carrying, were both burnt to ashes.
Harry Potter, who had survived an attack from Lord Voldemort, otherwise known as He-Who-Must-Not-Be-Named, was thereafter known as The Boy Who Lived For A Little While, while Albus Dumbledore was known as The Man Who Blew Up England Because He Didn't Know The Consequences of Apparating.