After his ignored shout of "Oi, ugly!" Severus picked up a rock with his off hand and chucked it at the large masked man. It hit him square in the back of the head.
That got his attention, and that of the two kids as well. Depending on how this played out, he might have to obliviate them. He kept his wand in hand but hid it behind his leg.
The man started approaching and then it happened: He contorted into the lifeless body of Lily Potter as he had found her that horrid day.
Severus stepped back a few paces and nearly tripped over the hazardous ground. He knew it wasn't real, but the vision before him made the loss feel real again, if only for a moment.
Anyway, that explained why the previous form looked vaguely familiar: The grubby man was in a horror film that came out when he was young.
...So recently...
It was a boggart, as he thought.
He looked up at the (now very confused) kids. "Leave." He ordered.
The boy dropped his makeshift weapon and hurried to assist the girl to her feet. They gave him and the boggart a wide berth as they cautiously hobbled around them to return to town. He watched the boggart half change in spasms when they stopped a few paces from him.
"What's wrong with...it?" The girl asked.
"...I don't know." Severus lied. "I thought I told you to leave."
"It was Leatherface before...What is it? What're ya' gonna do with it?" The boy continued.
"I don't know! Just get her out of here!" He gestured to the girl's injury.
Once they left, the boggart turned back into the still form of Lily. She was so young...Not as young as she was now...but she had barely started her life when she had been murdered.
There would be no early death for Lily this time, he would not allow it.
The boggart twitched and spasmed again and took a new form. That of Voldemort: the noseless bald edition. Nagini hung from his shoulders like a scarf, her tongue flickered out to taste the air. They stared at each other for a few moments before it shifted once more into a snarling werewolf.
Severus flinched but had a smile playing on his lips. It was confused, and attempting everything it could to make him scared. He refused to fear an imitation of his nightmares. He wasn't even sure he truly feared anything anymore, he had already experienced the worst life had to offer.
He did his best to find the humor in the boggart's desperate attempts and laughed. It was forced, but had the desired effect. The creature disappeared to wherever it resided in the woods.
He didn't have to use magic, thank Merlin. He didn't want to have to deal with the ministry.
Severus shoved his wand back into his jeans. He backtracked (at a significantly slower pace than sprinting) to find the location he left his belongings.
As he walked home, he wondered how that all played out when he did not intervene in his previous life. Did those muggle children (okay, they were about his current physical age…) have to be obliviated by the ministry? Did they go mad? Did the boggart hurt them? He didn't remember anything about 'something' terrorizing the woods outside of Cokeworth ministry must have brushed whatever happened under the rug and made sure nothing out of the ordinary was noticed.
He arrived home just as the sun was falling below the treeline. He opened the door to find his mother livid in the kitchen.
"You missed dinner. Where have you been all day?"
"I spent most of the day in the woods, actually." He held out the small bouquet he collected that morning to her.
She ignored the flowers. "You know how your father gets, he's cross."
There was a boggart in the woods. I rescued some muggles from it, without magic, not that anyone here would care about that. I think I'll catch it in my trunk tomorrow and leave it in father's closet.
"Where is he anyway?" Severus asked.
"Carl's."
"...I'll just go to bed then."
She sighed heavily and led (dragged) him to the table. She set down a plate of rice and beans with a roll in front of him. "Eat."
He held out the flowers for her again.
"Why do you keep shoving flowers in my face?"
"I'm not shoving them in your face, I'm giving them to you."
Her eyes narrowed. "Did you steal them?"
"No, I picked them in the woods...I thought you might like them."
She stared at them and then him as though he had grown another head. "Are you ill, Severus?"
Probably.
"Not that I am aware of."
"You were hanging around that Evans girl again, weren't you." She accused.
"I haven't seen Lily today, no."
"So, she didn't want to see you so you brought them to me instead?"
He scowled at her. "I picked them for you, Mum."
She frowned and gingerly took the flowers. She then realized she had nowhere to put them and appeared to be at a loss of what to do.
Severus watched her contemplate while he ate his cold dinner. She made to use a jar but deemed it too short.
When he was finished eating, he wandlessly conjured a vase with some water inside.
"No magic in the house." His mother scolded him but took the vase anyway. She put the flowers in it then placed them in the middle of the table.
"Yes, Mum."