Riverside Discovery
"Lily, don't wander so far away!" 10-year-old Lily Evans heard her sister shout to her from further up the river bank. She knew she shouldn't get so close to the murky water, but she needed to find a nice, flat rock to skip, and she was just certain there would be better ones under the low footbridge. But when she got there, she found something much more interesting.
"Tuney!" she yelled as loud as she could, "there's a kid under the bridge!"
Her sister joined her at the speed of light, and sure enough, there was what looked like a sleeping, naked child under the bridge. Petunia moved in front of her sister and went to look over the child, perhaps a young boy, who was laying face down. She rolled him to his side and - yes, definitely a boy.
"Hey, kid!" Lily stepped closer and started speaking, "Can you hear me?"
"I think we should go tell mum-" Petunia started to speak, but then the kid began to sputter and cough. His eyes opened - inhumanly large and slightly glossy - and widened at the sight of them. His eyes flickered from Petunia, to Lily, to the river. He looked back at Lily, and their eyes locked for a moment.
"Are you a-" As soon as she spoke, he jumped, pushing Petunia back as he dove headfirst into the river. Both girls gasped, and when he didn't return after a short moment, Petunia stood to take them home.
"That was odd," Lily noted aloud. "Do you think he'll be okay?"
"Best not to speculate," her sister said, though she was visibly confused as well.
But speculate Lily did, and she found herself once again drawn to the river the very next day.
---
"Water kid?" Lily called out, crouching under the bridge. She hoped to find, if not him, at least some sign that he was okay. After walking up and down the nearby bank a few times, checking under the bridge every time she passed, she was nearly ready to give up and go home. She changed her mind after checking under the bridge one last time.
As she glanced into the water, she could see him. Well, not him, exactly, but two, inhumanly large eyes looking back up at her. She stumbled back in shock, only for those same eyes to follow, poking up just above the waterline. He wasn't very visible, but it was definitely the same boy.
"Umm... Hello," she greeted him, to no response. He continued to stare at her, looking up and down as if searching for something.
"You startled me," she tried again, but as she stepped forward, he moved back. That was when she saw it, barely there, but visible through the water where the sun beamed through the bridge planks.
"Do you have a tail?!"
Clearly, it was the wrong thing to say, and he disappeared beneath the depths once more. She looked down into the water, only to find that he hadn't gone anywhere. Rather, he had flattened himself to remain fully submerged, still looking up in her direction. She decided to stay a while longer, to see if he would reemerge. When he didn't she wasn't dissuaded, and figured she would just have to come back tomorrow. Lily was determined to make a friend out of this little merboy, whatever it would take.
It was three days before he interacted with her again. Twice, she would see him above water as she approached the bridge, only for him to re-submerge himself as she got closer. Once, she tried reaching into the water, despite her mother's warnings to never touch it, only to come away with four burning scratches. This is what prompted him to surface. As she pulled her hand out and backed away from the water, the boy emerged, bringing half of his torso out of the water. He grabbed at her hand, looking guilty, but she took no notice of his actions. Her mind was fully preoccupied by the reveal of thin, leathery wings that were now partially out of the water. She only looked back at him when he grabbed her wrist and started rubbing on the scratches, making the pain more noticeable.
"Oh, I'm okay, don't worry about it," she pulled her hand away and opened her water bottle to pour clean water over the injury. It was all surface level, barely bleeding, and nothing to worry about. "You were just scared. I'm sorry, I shouldn't have tried to grab you like that."
He pulled back further into the water, looking slightly more relaxed, and she expected him to retreat back under. Instead, he rested his arms on the bank, re-submerging the wings, but leaving his shoulders and above visible. Still, he didn't speak.
"Do you... know how to skip rocks?" this was Lily's usual friendship tactic. She just hoped merchildren had the same interests as regular ones.
The boy briefly dipped back under the water, but returned quickly with a perfect, flat skipping rock. Rather than throw it herself, he handed it over to Lily, and she smiled.
So began an unlikely friendship.
---
That summer, Lily spent every day for the next week coming to talk to and play with the boy. Perhaps talk at more than talk to, because for the duration of their friendship, he still did not speak to her. She could, however, tell that he trusted her when he showed her his tail. As they played at the river bank, the boy pulled up a dead plant and threw it at Lily. He missed, but she decided to throw mud back at him in revenge, which landed. In return, she was splashed with the dirty river water, but not by his hands. He had used his tail to generate more force.
"Wow," she spoke quietly, "It's very pretty!"
He cocked his head for a moment, then shyly raised part of the fin above the water. It was scaly, with dark green and black coloration with a slight divot in the middle. Lily reached out, only for the boy to pull it back.
"Right, no touching. Sorry."
She went back the next day, as was routine, hoping she might see more if she asked politely. However, upon arrival to their bridge, she was that the boy was not alone, and his hair had been braided. Rather, he was being held closely by what appeared to be a woman, also with braided hair, also in the water. He didn't look distressed, and she didn't look dangerous, so Lily stepped under the bridge.
As she revealed herself, the woman parted her lips to reveal multiple rows of sharply pointed teeth, and the boy turned around. Upon seeing Lily, he began tugging on his mother's hair and leaned close to what she assumed was an ear, or the aquatic equivalent of one. After doing so, she hid her teeth once more and climbed out of the water.
Lily watched in astonishment as her tails - two of them - morphed into human legs as she fully emerged from the water. Her skin, once light at the front and dark on her back, evened out to a medium tone across her entire body. Her nose, which was nearly flat against her face in the water, gained shape, and her ears became human. The result was a naked but otherwise completely human-looking woman.
"You're Lily." It was more of a statement of fact than a question.
"Yes ma'am," Lily replied. She was surprised; she had just assumed that they couldn't speak.
"Thank you for looking after my daughter," she said, "But I'm afraid we must return home now."
Wait.
"You're welcome, ma'am. But, I thought he was a boy?"
The woman smiled at this. "You humans are so simple. Yes, I am aware that my child's human form is male, but that says nothing of her natural form. We have no way to even determine the sex of a child until they are of reproductive age, and my child's tail has hardly even begun to split yet!"
The boy - the child - batted at his mother as she said this. She spoke to him in a language Lily didn't understand.
"Besides," she continued, "Our language has no allowance for such pointless distinction. The best that I can do is make the closest translation for you."
That made sense, Lily supposed.
"Ma'am, may I ask you a question?"
"You may," the woman answered, "but I will not guarantee you an answer."
"Ma'am, are you a mermaid?"
She let out something between a huff and a laugh at this.
"Child," she said, "do not insult me. How old are you? Haven't you been to school? Severus says you have the Gift."
"I'm ten, ma'am, but I don't think I have any gift."
"That explains it," the woman replied. "Wait for your eleventh birthday, Lily. Then you will know whether or not you have the Gift."
She climbed back into the water, and her transformation reversed.
"I am sorry to cut your friendship short, Lily, but we must be going home now. My child has taken a liking to you; I'm sure you will hear from us again."
The child - Severus, now - waved to her, and they retreated beneath the surface.
When Lily returned the next day, as expected, they were gone.