I had kind of an interesting dream recently

It was late at night, on a dark, dingy street. Most of the buildings looked quite run-down, and there was hardly any light around, except just outside the place I was at, a club/music venue simply called Heaven. Inside the club, everything looked totally different. It was monochrome, and everything had a hand-drawn appearance, like an inverted pencil drawing (inverted because the background was black and objects were white). There were a couple of musicians on stage, a harpist and a pianist. The pianist was playing a big, fancy-looking grand piano that took up a large portion of the stage. Anyway, I was just chillin' here, having a drink with a girl, and chatting with various people. This girl was also a musician. I don't remember if she performed on stage that night, though she was another harpist. I recall that she was of special importance, because she wasn't a human, but some sort of spirit who acted as a guardian to this place. As I was hanging out, the piano on stage started to rust very suddenly, though it appeared to stop after a moment, leaving behind a splotch of rust on the side. This created an air of unease in the club, as people seemed to be worried about something specific. I got the feeling they knew something I didn't. One young boy asked, "The infection couldn't reach us here, right? Not in Heaven?" The spirit girl and some other adult reassured him. The musicians returned to playing and people tried to ignore the strange event for some time. A few moments later, however, the splotch of rust began to grow again, and out from it emerged a phantom, who wore a suit, a cape, and a masquerade-style mask, and he had a cane as well. As he jumped out, everyone ran out in various directions, though the phantom chose to pursue me. He flew towards me rapidly, with his cape seeming to act like wings, whilst chuckling villainously. I ran around the city for hours trying to lose him. The streets seemed strangely devoid of people. There were also no cars driving around, only a few parked ones.

The dream ended suddenly as I was running, I think. You could call it a nightmare, because it was kinda scary in the moment, but thinking about it after waking up, it seemed kinda cool. It had some interesting concepts, so I've thought of fleshing it out and making some kind of story out of it.