Coming back to 12 Grimmauld place after he ran away all those years ago was something little Sirius would've scoffed at, yet he had to return, much to his dismay. But, when he did return.. it was different. Very messy. And Kreacher refused to tell why he hadn't cleaned it up.

While he stayed there, bored out of his mind with Buckbeak, paranormal events started occur. Sure, that wasn't that alarming since magic is a pretty common thing, but it was only him in the house, with Remus only visiting occasionally.

Then, while descending the stairs, he saw quite an odd sight at the bottom. It was his brother and a kid that couldn't be more than nine. The child was talking excitedly about a toy doll they had in their hands as his brother watched. But they were translucent. And his brother looked a lot different from when he last saw him, which did make sense, since Regulus was bound the grow up while he was gone, but he looked wet and scratched up. The kid also had a lot of bruises all over them..

Oh. They were ghosts.

It was clear the both of them had noticed him by the time he had this realisation. From then on, they didn't bother hiding from him. Yes, they still messed with him a lot, but he started talking to the kid. Not his brother, though. He wasn't ready for that.

Speaking of you, he was currently laying in bed, staring at his ceiling before a stuffed doll entered his vision. It looked down at him and its arm got lifted up as if to wave. Letting out a small laugh, he lifted up a hand in response, as if greeting in back

“Hey, kid.”

You suddenly flashed into existence above him, your chin resting on your palm as you float above him

“Whatchu doing up there, huh?”