If Severus had thought things were bad with his dad before, they were nothing compared to the way it was once his dad had found out he could do magic. After that day in the living room, Tobias had been more cautious around the pair of them, and Severus started to hope that things would get better. But it didn't last long.
Little Severus continued to cast Shield Charms whenever his dad was in a rage, and Tobias eventually caught on. He hadn't trusted Severus' mum's explanation from before, and his continued inability to beat on his wife confirmed for him that Severus was just like her.
His anger about Severus' abilities was severe and far-reaching. He starved Severus for nearly a week, trying to drive the magic out of him. When that didn't work, he locked Severus in his room, but Severus soon learned how to magically open the door. Tobias finally attempted to physically chain Severus to the bed, but when Severus heard his mum crying, the cold steel turned as warm and pliable as clay. By the time he was five years old, Severus could wiggle his way out of anything his father used to restrain him, and he had more control over his abilities than any child his mum had ever seen growing up in the Wizarding world. This both worried her and made her exceedingly proud.
October of that year marked the first time that Severus used magic purposefully against another. Several neighborhood boys had taken particular notice of Severus and his dingy gray clothes. The oversized rags were all Tobias allowed him to wear, as Tobias' money primarily went to booze and whores instead of coal for the fire or food for their bellies. Severus' undeniable air of "differentness" drew the bullies like nifflers to gold.
"What are you reading, Snapey?" the largest one, Marcus, asked. Snape knew better than to answer, and forced himself to remain still. He knew from experience that running would only make the inevitable beating worse. Beating… wait… Severus realized that he didn't have to sit back and allow these miniature Tobiases to bully him. Not anymore. Not since he'd discovered he was magical.
"Potions? What stupid book is this?" Adam, one of the smaller boys, ripped the book from Severus' hands and threw it in the mud.
The shield sprung up so fast and so strong that all of the boys were knocked off their feet, including Severus. He was the quickest to recover, however, leaping to his feet and grabbing his book. The boys began to stand, as well, advancing on Severus once more.
"Neat trick you got there, Snapey," Marcus taunted him. "But-"
His threat was cut off as Severus knocked them over again. This time he remained standing, and the boys began to look nervous. As they started to rise, Severus focused on what he wanted – and knocked them over, again.
Now the boys looked genuinely scared, and a vengeful smile bloomed on Severus' small face. As the boys tried to run away, he held out his hand, palm forward, reveling in his power as he knocked them over again, and again, and again. As they turned the corner, crying, Severus laughed in delight. No one would be able to bother him ever again!
At that moment, his mum came racing out of the house, a sight which so startled Severus that he stood there, hand still out, mouth agape.
"What are you doing?" she cried, grabbing his arm and brutually tugging him back inside. "We've talked about this, Sevvy! You can't do that with people watching!" Her wide eyes darted up and down the street.
He didn't understand why she was so frightened. Didn't she realize how wonderful this was? Those boys wouldn't be bothering him any more, and if they tried – wham! He'd take care of them. A wondrous smile lit his face at the thought.
"It's okay, Mum," he explained. "Those boys won't-"
"Don't you remember what I told you about using your magic?" his mum hissed frantically. "Not in front of anyone but me! Not against people! Oh, I hope no one saw…" She peered out of their front curtains nervously.
"I use it against Da all the time, though," Severus reasoned. He really didn't understand the difference.
"You- That's- Oh, it's not the same," she blustered. "Your Da, well, he already knows about our magic, doesn't he? But no one else does, and they can't, Sevvy," she whispered. "Besides, you can use it to protect yourself, yes, but it should never be used to attack! What you did to those boys was wrong."
"How come you don't do magic to protect yourself from Da?" Severus asked, curious. His mum's face froze before she turned away.
"That's none of your business," she said crisply. "Go on up to your room until dinner."
His mum was distraught the rest of the afternoon. As Severus lay on his bed, he pondered what she had said to him. Surely what he'd done was just self-defense? He'd enjoyed it, yes, but if he hadn't knocked those boys down they would surely have beaten him up. Right? And why didn't his mum shield herself from Tobias' fists, anyway? Severus was very troubled. If magic was real, if they both had it, why did they stay with Tobias? Why didn't his mum just make it all better?
That night as he drifted off to sleep, Severus decided that his mum was wrong. He had needed to use his magic for his own safety, and he would not hesitate to do so again. He never wanted to feel powerless again in his life – never. And he would do whatever it took to ensure that.
A/N: Not JK Rowling, and I (sadly) don't make any money writing. Writing Severus' childhood is terribly intimidating, but I hope I'm going to do him justice. There are about 6 more chapters planned.