The door exploded in a shower of splinters.
On the porch stood a figure that could vaguely be defined as being human. It had the right shape and size, but its perfectly smooth tan skin was only marred by large fiery hot fissures, nothing resembling a face.
Dudley Dursley stared at this figure, and then two gaps appeared in its face burning with a fierce red light. A large rift appeared near the bottom of its face, and it was filled with jagged protrusions of bone.
"Dudley..." the figure rasped, "I believe I have a debt to repay you."
There was a loud pop and suddenly the figure was behind Dudley. Its hands wrapped around Dudley's throat and began squeezing. Dudley fiercely struggled and felt the burning sensation of not having enough to breathe. As he was about to black out, the strangling sensation disappeared.
Vernon Dursley was holding his shotgun and was pointing it towards the figure. "GET AWAY FROM MY SON, FREAK!" Vernon screamed trembling.
Faster than the eye could follow a slender holly wand flew into the figure's hand, twirling the wand in a fashion not dissimilar to an orchestra conductor, the figure spoke, "Baelus Invicare".
A jet of hot white Fiendfyre streamed from the figure's wand, shapes and creatures writhing and struggling within the flame. A large serpent had taken shape and coiled around the shotgun, turning into a heap of molten metal, then immediately crawling up Vernon's arm, causing his flesh to drip off like wax.
A herd of elk followed the serpent running across the ruin of Vernon's arm, singing and fracturing the bone of his arm. Finally, the serpent burrowed into Vernon's stomach, burning and consuming him from the inside out. As Vernon's flesh began dripping and his bone chipping away and falling into the gaping cavern that was now Vernon's stomach, and as his organs and blood boiled, he managed to gurgle one last thing, "Freak..."
Then Vernon's molten corpse exploded splattering Dudley with the still hot fragments of his father's corpse. As they left burn marks on his body, the figure pressed his wand into Dudley's back and held it there. Dudley squirmed and began crying, the anticipation of the horrible thing that was going to happen to him nearly driving him mad. Dudley's fate was prolonged by the shriek of Petunia.
"Bombarda" yelled the figure swinging his wand away from Dudley. A large boom echoed throughout the house as plaster and wood flew through the air.
Petunia had been flung against the wall hard, with a sickening crunch, then she fell ten feet down through the now non-existent floor she had previously stood upon. Both her legs shattered and twisted at odd angles.
"Ennervate" the figure calmly intoned, and Petunia screamed once more as she felt her shattered limbs.
"Agrioventi" the figure spoke and a stream of acid blossomed from his wand and fell upon Petunia. As her skin and the muscles beneath began to froth and dissolve, the figure raised his wand once more, "Elektreus" and a bolt of miniature lightning struck Petunia causing her to spasm even as she lost more blood and dissolved.
Dudley began to try and run away, and he had gotten to the open doorway, "Tarentellegra" the figure spoke and as Dudley began dancing causing him to trip. Dudley broke several teeth on his fall filling his mouth with the coppery taste of blood. The burns on his body began to become aggravated due to the spasming he was now doing thanks to the Tarentellegra curse.
Suddenly a force began strangling Dudley and started dragging him towards the figure. Dudley was suddenly unable to move and merely forced to watch. "Accio Spine" the figure stated and Petunia's spine tore out of her body and through her chest, carrying skin and organs with it. The trauma killed Petunia, and the figure whispered "Bombarda" once again splattering Dudley with gore.
"Best for last..." the figure spoke gazing at Dudley.
"Accio Intestines" the figure spoke, and Dudley screamed before anything had happened.
As he felt himself vomiting out blood and his intestines began shooting forth from his mouth, he lost consciousness.
He awoke and felt very dizzy. In front of him was a huge tangled pink and purple snake, as memory returned to Dudley he realized they were his intenstines.
The figure slashed his wand downwards and tore open Dudley's stomach, causing the stomach acid to spill and soak Dudley's organs.
As he began to die, the last thing Dudley saw was the faded lightning-bolt scar on the figure's forehead.