Disclaimer - I don't own Harry Potter. This is written for the second regular challenge for November 2021 - paranormal.

Upside Down Mirror: Granger Yet
Ghost Sighting

"Regulus!"

Sirius watched as Regulus didn't turn and acknowledge him, yet he was sure that the young man walking away from him was in fact his younger brother, very much alive, a strange paranormal event that Sirius couldn't in any way explain. He hurried forward, latching onto the sleeve of the young man and tugging on his arm so he couldn't ignore him.

"Regulus!"

"I don't know you," the young man with shaggy black locks of hair turned around and looked at Sirius with familiar-looking eyes that reminded him so much of his younger brother's eyes. Sirius was sure that, despite the young man saying otherwise, that it was Regulus.

"You're lying." Sirius tightened his grip on his sleeve, becoming angry as he did so. "You are Regulus."

The young man looked at Sirius's hand in disgust, much as Regulus did back at Hogwarts. "My name is Sebastian, but as I said, I don't know you."

"No. You're name is Regulus. Regulus…"

"I don't have time for this. I'm supposed to be heading home to study for my A-levels," said this Sebastian who was just as studious as Regulus. "So could you let go of me?"

"No. You're Regulus." Sirius paused. "What are A-levels?"

The young man's mouth twisted slightly. "Everybody knows what A-levels are. How can you not know what A-levels are?"

"I…"

"Hey!" Someone yelled. "Leave my brother alone."

Sirius stared at a person with brown hair and brown eyes. The next thing he knew, the person claiming to be Regulus' brother clocked him. He staggered back while the other person pulled the young man away, but he was sure when he looked up at the young man that he stuck his tongue out at him in a cheeky manner which—

He stared, confused.

"Sirius!"

Sirius turned to look at Remus. "It's not him."

"What are you talking about? We're on a mission from the order, remember?"

"Regulus would never stick his tongue at me. And what are A-levels?"

"They're," Remus frowned. "The Muggle equivalent to our N.E.W.T.s."

"Then, he was a Muggle who looked like Regulus and not Regulus," Sirius murmured. "He looked so much like him. The look on Remus's face—" I know. I know. I need to get my act together. And don't tell James or Lily. It was—It was like seeing a ghost."

—a strange paranormal event that Sirius definitely couldn't explain, beyond the fact he found himself haunted by Regulus' death and it started to affect his mental state.

"Breathe. Take a deep breath and you'll be fine," said one of Olivia's brothers, the one who managed to run into him when he ran into Sirius.

How he'd not given himself away, Regulus didn't even remotely know, let alone understand. He wanted to scream at his older brother—his biological older brother, not to touch him, that he'd walked away all those years ago.

Yet, another part of him wanted to admit to Sirius, now that he was looking at him—actually looking at him and acting as if he were wanting to interact with him. " That 's a lie. That's a lie and I know it. He was simply surprised to run into you, at all. He would have turned you in, had he known. He…"

"Sebastian? Did you know that person?"

"I…" Regulus closed his eyes. He felt tears well up.

"I'll take that as a yes. Maybe we should avoid that part of the village for the time being?"

"I guess. He—"

"You don't have to say, but we'll all keep you safe."

"Is Sirius someone I need to be kept safe from?"

"Why don't we head home to Olivia and your baby girl now."

"Yeah. I want to see them both."