Sirius thinks he sees a ghost, so to speak. Disclaimer - I don't own Harry Potter. This is written for the second regular challenge for November 2021 - paranormal. For those who've read some of my other stories where Regulus is Hermione's father, I left it open as to which of his brothers-in-law confronted Regulus, but it's also one of those stories which may or may not happen within the timeline since it was based on the question of if Sirius ran into Regulus, but him thinking he's seen a ghost is how I tied it to the word prompt.