Severus had heard a lot about Petunia Evans from Lily, back before he irrevocably ruined their friendship forever, but nothing she said could have ever prepared him for his first meeting with the girl face to face. Affectionately called "Tuney" by her family—and scathingly referred to as "Loony" by just about everyone else, Petunia Evans was about as odd as they come.
According to Lily, on Petunia's tenth birthday, she had tripped on her way down the stairs, hitting her head so hard that she had fallen into a coma. When she awoke seven months later, she remembered nothing of her life, and called herself Luna. She spoke of ridiculous, non-existent creatures with equally ridiculous and non-existent abilities. When her behavior began to garner some decidedly less than pleasant attention, Lily and her parents went to great lengths to protect her from the worst of it. Petunia spent so much time with her therapists and at her school—whose name Severus was never told—that in his seven years of knowing Lily, he'd only ever had the barest glimpses of her. He had asked once why Lily never attempted to introduce him to her sister, whom she spoke of with such fondness, and she smiled at him apologetically.
"You can be kind of mean sometimes, Sev," she had said carefully. He had been offended for only a moment, before admitting, if only to himself, that she was right.
After that, he hardly ever entertained any thoughts of meeting her in person. And then he and Lily had that falling out last year. Meeting Petunia Evans went from being an improbability, to an impossibility.
"Nice to see you again, Professor Snape."
Yet here she was.
"Professor?" He wasn't sure how, but he managed to make it sound like a question, statement, and a condescending sneer all at once. It was something he felt he should learn to replicate. It could come in handy one day.
"Well, not yet. But someday. I'm sorry." The sentences were short and choppy, and Severus was finding it hard to decipher their meaning.
"Who are you?" He asked, though he knew the answer already.
"Loony Evans," she replied easily, her wide blue eyes locked on his own dark ones.
"Yes. I've come to appreciate it. It's familiar, you see."
They stood there staring at each other, and he was beginning to feel even more awkward than he had at the start of their encounter. Thinking of that, Severus suddenly remembered something odd about what "Loony" said, other than calling him "Professor."
"'Nice to see you again'? Evans, we've never met before."
"No, but we will," she told him solemnly. At her nonsensical comment, Severus had to calm himself before he started throwing hexes. "Oh, I recognize that look. Have I annoyed you, sir?"
She wasn't apologizing for annoying him, merely looking resigned to the fact that she had, as if she'd done it often.
Without warning, so quickly that he hadn't even registered her moving, she latched onto his left wrist, pulling his arm toward her. Pushing his sleeve up swiftly, she began inspecting his forearm as his brain tried to catch up with what just happened. When it did, he yanked his arm away, adjusted his sleeve, and glared at her fiercely.
"What the hell do you think you're doing?"
"Hmm... Bare," she mused, ignoring his indignation. "Still early. That's good, I suppose. You know, you don't have to ruin your life."
"Excuse me!?" Severus snapped, hiding how disturbed he was by the sudden focus in her gaze.
"The war on blood supremacy will only end with unnecessary bloodshed. Too much will be lost."
Severus felt his body tense with every word she spoke. Not the warning, per se, though that was rather worrying. But no, what really froze him in place was the fact that she even knew what was going on. Lily never told her family about how bad the Wizarding World could get.
"I just don't want them to worry, you know," Lily told him as they sat in their compartment together on the Hogwarts Express, smiling sadly as she waved to her family on the platform. "They already have so much to worry about, what with all of Tuney's bills, and her school trying to pass her off to some facility in America "more prepared to deal with her...unique mental physiology." Condescending cow. She and the rest of that stupid school are just completely incompetent and should obviously just learn how to actually do their job instead of trying to play it off as Tuney's fault."
Severus had almost wanted to laugh at the clear derision on her face, her scowl one he was sure she picked up from him.
But right now, the last thing he wanted to do was laugh.
"How do you know about that? I highly doubt Lily decided to tell you about everything she's been trying so hard to hide from you guys."
"I didn't need to be told how it is, I already knew how it will be."
"Are you trying to confuse me?" Severus blurted out before he could stop himself.
"No, but is it working?" She asked curiously. He didn't respond, but she nodded resolutely as if he had. When he continued staring at her, she turned her gaze toward the sky and hummed. "It's about time I go home now. Mum promised we'd have pudding for dinner. Goodbye, Professor. We should meet up again soon."
He would've retorted with a "Not bloody likely," but she had already spun on her heel and...disapparated. That wouldn't have been so weird, if Severus didn't already know for certain that Lily's sister was a muggle. Not a muggleborn, but a muggle.
Maybe they would meet again, if only so that he could get to the bottom of the mystery of Loony Evans.
AN: So, something a little different. Luna Lovegood as Petunia Evans - not Dursley, because I can't imagine any reason Luna would marry Vernon. I have been working on this since I heard about Alan Rickman, it just took awhile to get it right.