Nightly occurrences in an apartment building: a black dog and rattling elevators

So one time my girl wakes me up, says, anon, I'm scared, there's a dog running around our building (!). Half-asleep I don't understand shit, what the fuck dog. The girl says well look through the peephole. I look - and there really is a dog racing up and down the stairs, black, bony. With this clicking from its claws on the concrete. Runs by every couple of minutes. Well I think some asshole left the building door open again, so this flea-bag ran in to warm up. But it looked creepy, imagine, in the semi-darkness of the stairwell a mutt is silently racing around, no barking, no whining.
The thing is, during the day the dog disappeared somewhere, but the next night it showed up again. And the next, and the next. The neighbors didn't notice either, one guy went out to chase it away, and it bit his hand and fucked off. Damn, he raised a racket, he survived.
And right after that, like starting the very next night, someone took to riding the elevators. They were still old, Soviet, rattled like a motherfucker, I could even wake up from that when there are no other sounds. Somewhere from midnight to 3-4 a.m. some asshole was riding up and down, banging the doors, both elevators going at the same time. Once I couldn't take it, grabbed a little crowbar and called the elevator, thinking I'd beat the shit out of some junkie. The elevator arrives - and there's no one inside. But inside everything is smashed to hell: mirror broken, buttons as if someone tried to rip them out, all the walls in some fucking scratches, smells like something.
Just as I'm thinking WELL WHO THE FUCK WAS RIDING THEN, I hear someone calling the second elevator from below, getting in and starting to come up. And it starts, fuck, rattling. Like some fatso is jumping in there and simultaneously pounding on the walls. And with every second this rattling elevator gets closer to me, to my floor. That's when I shit a brick and fucking bolted back to my place, locked all the locks. Through the peephole I see - the doors open on my floor, no one comes out, the elevator goes further up and someone keeps furiously rattling, like they're going to wake up the whole building. I finished my sleep in earplugs.
And soon I'm going to work in the morning - and downstairs there are neighbors, an ambulance, all that shit. Anyway, some drunk old man also got fed up with the fucking night elevator operator and went out to sort it out like a man. Only he didn't chicken out like me, he waited for the elevator to arrive. After that no one knows what happened to him, but in the morning a neighbor woman called the elevator, and it arrived with this old man's corpse right there. A blood clot broke off.
After that the creepy shit just stopped