A constant, gentle poking awoke Freak from his unconscious state. Groaning in discomfort, Freak shifted before opening his eyes, frowning at the feeling of objects digging into his back. Shock quickly overcame the discomfort though, when Freak got a look at his chest. Through the shredded pieces of what used to be his shirt, Freak could see blue fur where his skin used to be. Numbly reaching up to touch it, Freak froze once more, when he saw three fingers coated in the fur, rather than his five-fingered, skin-covered hand.
Before the boy could go into non-responsive shock, an envelope addressed to 'My Son' magically flew into his outstretched hand and lay there, as if waiting to be opened.
Finding the idea of someone sending him a letter, claiming to be a parent to him or not, much more interesting than his current condition, Freak decided to open it.

My dear, sweet son,
I hope that this letter never finds you, for, if it does, it means I am dead. I have dreamed of watching you grow up to be a wonderful and strong young man, but it seems I never got to congratulate you on your seventeenth year of life. First off, happy birthday my love! As you most-likely already know, if a wizard has creature blood in their family, said wizard will gain a creature inheritance on their seventeenth birthday. You may have thought you wouldn't be getting one, as your father's side of the family is not known for creature blood, but mine is very deeply intwined with it. Believe it or not, my son, but I am not human, nor was I ever. I am from a race called Nightcrawlers, which may remind you of the worms that live in the dirt, but we are a much superior race to human- and wizard-kind. Sadly, our race has nearly died out, and if you are reading this, then it means you are the last one of us alive. We have never been documented as a species, as our home is not on Earth, so I will have to tell you all of what being a Nightcrawler entails, but not here. In my vault at Gringotts- you will find the key to it having come with this letter- there is a chest full of books that I have filled with information on our species, as well as a journal detailing my integration into human and wizard society. To tide you over for now, as I hope you have a curious mind like mine, Nightcrawlers all have share similar traits and duties. All of our kind have blue fur covering the entirety of our bodies, glowing eyes of various colors, sharp canines, and pointed ears. Every male has a prehensile tail as well. Each of us does have our differences though, as some may have extra arms, extra legs, less fingers/toes, more rows of teeth, longer tongues, more/less eyes, different tail types, etc. Many of these aspects can run in families as well.
And just as appearances run in a family, our species' abilities and duties differ depending on the family as well. But our family, specifically, is a conglomeration of many, since our family is the last one surviving. Your full duties can be found in my journals, but there is one that I hope to never have to give you, the duty of Defender. This task is usually granted to the King of our race, but after an intelligent attack, his family was completely slaughtered. Our family was closely related to his, and that is the only reason I know of this task. You must not tell anyone else, even your most trusted friends, because this secret is the only thing that may keep our species alive. It is up to you to accept or decline, but the Earth depends on your choice. If you decline, the balance will be ruined and the apocalypse will begin, but should you accept, you will lose your soul and gain quasi-immortal life. I say quasi as the only way to kill you would be through a clean decapitation, as not even old age will affect you. I have hope you will never have to use this information though, because you are my baby, and I would never wish my burden onto you.
To get off of this morose note, for I no longer wish to think of it, I will give you a basic idea of what Nightcrawlers' abilities are. Compared to other races found on this planet, we have enhanced speed and agility, unmatchable hand-eye coordination, vast reservoirs of magic, strong adhesive hairs on our hands and feet, increased regeneration, and near-perfect night vision. There are some capabilities that are not commonly found here on earth, and they are some of the best, in my opinion. Our ability to summon bamfs- a servant race very similar to house elves- through the spilling of our blood and disappear into shadows are specifics to being a Nightcrawler. You may find the rest of my information on Nightcrawlers in my vault- for I can see how long this letter already is- as I have it waiting for you, just in case.
To be brief with the other matters I need to disclose here, the suit you will find that comes with this letter will always fit you, no matter how you grow, as I have heard of how tedious it can be to make holes in your clothes to fit your tail exactly from my father. There is also a necklace that is in the hidden pocket of the suit. This necklace is to help you blend in with the humans of this world. It will hide the specific aspects of our species that do not coincide with the appearance of a regular human. It is charmed to never come off once put on, but the visage can be dispersed if you merely tap the center of the pendant with a finger. Your magic will do the rest for you.
My dear boy, how I wish to hold you as I write this. In my time, you are still a baby growing in my stomach, but I can tell that you will be a handsome, lovely man someday. It will be my greatest sorrow if I cannot be there to watch over you as you grow up. Know that, even if I have not seen you, I will always love you the way a mother only can. No matter what you do, I know I could never stop loving the little baby that kicks whenever I sing and stays still when I read him a story. Please, never forget me? If I end up being gone for any part of your childhood and you see someone else as a mother figure, know that I could never hold it against you, but just remember that there is someone else out there that loves you even more than they do, okay? I know you are my baby, but it always hurts to be forgotten. Please, live your life the way you want to live it, and enjoy as much of it as possible. I pray to God that this letter finds you well, my beautiful baby boy.
With eternal love,
Mum

Freak lightly put the letter down, not wishing to ruin anything that his mother could have given him. Thinking over what he could understand from the letter, Freak couldn't stop the tears that fell from his eyes, glowing eyes, if his mother was right. His mother was confirmed to be dead, and he was no longer human, but the last being of an extinct, alien race. A watery smile came to Freak's face as he likened his situation to that of Superman. The only exception was that Clark looked human and had a loving family to support him.
Dredging up thoughts of his wonderful treatment at the hands of his 'family', Freak felt numb as he realized he would be thrown out now, or simply killed. If last night was an indication of what the Dursley's would do to him now that he looked like this, imagine the kind of pain he could be in.
Freak couldn't. He didn't know what could be worse than last night, and he didn't want to know. He quickly decided that he needed to get out of here- tonight.
Getting into action right away, and momentarily forgetting about his mother's letter, Freak patted down his torn pants to make sure his wallet was on him, only to freeze when he didn't feel the normal bulge where it had been for the past few days. Frantically standing up, and nearly pitching to the side, Freak was forced to pause in his actions and recollect himself. Staring at his feet, Freak stared in wonder as he twitched his two toes, which more closely resembled talons, if he bothered to think about it. Cautiously taking his hands from their support on the walls, Freak balanced carefully and squatted, testing his balance. It shocked him when he simply flowed through the movement, coming back to stand straight up without a hint of wobbling. Not so easily appeased, the six-year-old brought one leg up into the famed 'Karate Kid' position. Raising an eyebrow at the length of his foot, which was a lot longer than it used to be, Freak squatted again and didn't waiver once. A small smile spread on the boy's face as he twirled on the tips of his 'toes' like a ballerina. Giggling lightly, he continued to spin until his eyes caught an odd piece of fabric hovering in the air near the door to his cupboard, which he realized was dark, even though he could see perfectly. Remembering that his mum had mentioned night vision, Freak cautiously reached out to the cloth and didn't flinch as terribly when it flew into his hand, much like the letter. Spreading the material between his two hands, Freak thought it was a bodysuit of some kind, but couldn't really tell, as the thing was big.
Suddenly, the suit grew taught in his hands, as if something was tugging at it from the other side. Pulling his hands down to get a better look, Freak saw a length of blue fur ending in a spade curling around the end of the suit. It would seem he had found his pre-hen-sill tail. Smiling in glee, as what child wouldn't want a tail, Freak returned to holding the suit up and inspecting it, enjoying the help his tail gave without needing any prompting.
The material seemed to be a suit, but Freak couldn't figure out how anyone would be able to wear this, much less him. It was huge. Still, Freak glanced at the state of his clothes, he needed something to change into, and his old clothes wouldn't have a whole for his new tail. Plus, he's worn large stuff before, as Dudley's old clothes weren't exactly small.
Shrugging to himself, Freak shucked off the remains of his tattered clothes and slipped the bodysuit on. Getting his tail through the little slot for it was difficult, as the stupid thing didn't want to stay still, but after a few minutes it wriggled through the hole and snaked out of Freak's grasp. Giggling lightly as his tail booped him on the nose, Freak flailed his arms around wildly in the suit, flopping the sleeves all around.
A few minutes after playing tag with his tail, Freak inspected the fabric a little bit closer, as he could feel an odd warmth against his fur from where his body touched the material. As if awaiting his question, the suit shrank out of Freak's grasp and fitted to his body in a matter of seconds. Freak stood in shock for a few seconds, before warmth permeated his bones. He hadn't known how cold he really was until that moment, in that dank cupboard under the stairs. It was as if he could feel his mother's love through the magical fabric.
Another thought quickly overcame the little boy as he marveled at the reality of magic being real. If the suit really could fit him in any shape, was there a secret pocket with a necklace that would make him look human again?
Excitedly feeling around the suit with his hands, Freak frowned when he couldn't feel any bulges indicating a pocket.
Slumping lightly, Freak almost flinched when his tail lightly tapped him in the center of his chest. A small pocket opened up at the separation between the two colors that seemed to make up the bodysuit, though they were hard to figure out with his monochrome night vision.
Gently reaching inside, Freak frowned when he saw his whole fist slip into the small pocket before touching something. Grabbing it and pulling his hand out, Freak was happy to see a silver necklace come out with it. Holding the piece of jewelry closer to his face, Freak recognized the cross from his few visits past the church his relatives went to every Sunday. He never got to go along with them, but now he would be able to bring his own little church with him wherever he went.
Smiling delightedly, Freak found the clasp for the necklace and fastened it around his neck, but only after stumbling a little bit with his new, three-fingered hands.
Face nearly glowing with the force of Freak's anticipation, he touched his middle right finger to the center of the cross. Less than a second later, Freak saw skin where he had had fur, and a set of regular clothing on him.
Jumping up and down in his excitement, Freak felt all over his body to see if everything was hidden, only to realize that his tail was gone too. Panicked, Freak tapped the cross again and watched, entranced, as his skin fizzled away and his tail reappeared, wrapped around his waist. The little guy waved to him before going back to swaying behind him. Freak giggled before giving a little yawn, rubbing at his eyes tiredly.

-

A few hours later, when the sun was beginning to rise in the sky, Freak awoke in a cold sweat. Realizing he had accidentally fallen back asleep, and had a nightmare, after testing out his hidden pocket, Freak quickly jumped up and began stashing the few things that he wanted to bring with him into his pocket. Freak's newly amplified sight helped him pick out the objects he wished to take along with him faster than when he had regular sight. Seeing that everything was packed, Freak froze for a second, making sure that the house was completely asleep before he picked the lock on the cupboard.
Sneaking into the kitchen that was still bloody from the night before, Freak wrinkled his nose at the acrid smell and had to quell the panic he felt converge on his consciousness at the reminder to his newest nightmares. Freak took a deep breath and looked around for where his wallet may have fallen out of his torn trousers.
After a few minutes of thorough searching, Freak realized that it wasn't anywhere in the kitchen. Anxious at the passing time, for the longer he stayed the bigger the possibility that his relatives would wake up, Freak figured that Vernon must have taken it with him to his room.
Quietly creeping up the stairs to the master bedroom. Freak prayed that the door hinge wouldn't squeak as he opened it. Grimacing in anticipation, but opening the door anyway, the boy felt blessed when the door didn't make a sound. Taking a second to heave a deep breath and steel his nerves, Freak slowly entered the dark room.
Approaching the nightstand where Vernon normally put his things, Freak had to calm himself down again as he adopted an intense feeling of fear and anxiety. Reminding himself that this man wouldn't be able to hurt him anymore once he was gone, Freak inspected the small stack of chaos that was breeding on his Uncle's nightstand, and felt his stomach sink when his wallet was no where to be found. Quietly opening the small drawer inside the nightstand, Freak perked up at the sight of loose pounds, and quickly pocketed them, but noticed his wallet was still absent. Closing the drawer up and stepping back, Freak let his glowing eyes sweep across the room until they fell upon a messy pile of Vernon's clothes from yesterday.
Nimble as a mouse on his two-toed feet, Freak dug through the bloody pile of clothes with a grimace, ignoring the flashes of pain, desperation, and blood as best he could.
Finding his wallet less than five minutes later, Freak couldn't help but collapse backwards onto his side, curling up into a fetal position as his tail swung menacingly above him. Pink tears fell from his eyes as he gasped, clutching the wallet tighter in his fists. He had found Vernon's belt right next to it, and was hit with a large torrent of memories as he was forced to feel the ghost pains. Whip marks and lashes dug into his back; blood, tears, and salt infected his cuts; and his lungs burned as bruises formed around his neck. He wished to move, but too many important bones had been fractured to allow much without an added onslaught of pain. Why would his uncle do this to him, he would never know.
Whimpers rang through the bedroom as Freak tried to break out of his reverie, but it was too late, as something else woke up before him.
A snort and gruffly mumbled words, along with sharp whimpers and crying caused a skinny woman to be awoken from her light sleep. Sighing lightly, Petunia rolled onto her back to stare at the ceiling, wishing to fall back to sleep in her comfy bed, next to her warm, handsome husband. The silence that surrounded her was peaceful, but it oddly reminded her of the baby cub she had seen on the tele when her Dudley was watching a lion documentary.
Hearing a sharp whine echo in her mind, Petunia sat up with wide, horrified eyes as she looked around the room slowly, too terrified to move too fast. Steadily moving her head from one side to the other, the woman caught sight of a flinching tangle of limbs in the corner of the room. The idea of being robbed flashed into her head, but something was different about this person.
A moment later, Petunia dropped all pretenses and shook her husband as hard as she could. The thing was waking up.
A haunting groan echoed through the room just as Vernon spluttered awake. Harshly pinching Vernon's lips closed to keep him from making any loud noises, Petunia got her husband's attention and pointed to the corner of the room, where the... thing was getting up.
Whipping his head to look in the direction his wife had pointed, Vernon's pudgy eyes narrowed when he spotted the small, flickering form in the darkness. Noticing that it didn't know they were awake yet, Vernon slowly reached under his side of the bed and withdrew his trusty shotgun.
Freak was instantly on alert as he heard a loud click resound in his uncle's bedroom. Turning his glowing eyes to the bed, Freak grew terrified of the sight before him. Both of his relatives were glaring at him, and his uncle had a shotgun pointed directly at his head.
"You have three seconds before I shoot."
Eyes widening even larger, Freak smushed himself against the wall behind him as Vernon cocked the gun.
"Three..."
Freak couldn't restrain himself from shaking, his eyes darting around the room to find an escape. The window was on the opposite side of the room and any sudden movements would cause his uncle to shoot.
"Two..."
Grasping his necklace and praying to God, Freak wished to leave this place and go somewhere else, anywhere else, just away from his relatives, away from Britain.
"One."
A bamf echoed through the room, but no gun was fired. A bright, purple light slowly fizzled out from the corner of the room and the couple was finally left alone.