When I was in my early twenties, I lived with my brothers in my oldest brother's house. It was a new construction home in a fairly ritzy suburb of a large city in the US.

During this time, I was attending college and working part time at Gamestop. One of my brothers was working at Chipotle at the time, so there were some afternoons that we'd both have off and we'd be chillin at the house together. One afternoon while my oldest brother and his wife were at work, my brother and I were in the living room playing Diablo 3. All of the sudden I hear this weird old song playing from the loft and I instantly whipped my head around towards the loft, trying to figure out what tf it was. It wasn't a song or a tune I've ever heard in my life before. The thing is, my brother whipped his heads towards the loft the exact second I did because he heard it too. We looked at each other for a second, and decided to investigate. Everything in the upstairs area was ours, too - we moved in right when my oldest brother and his wife bought the house, and they left that whole area for us. We both knew we didn't own anything that could've played the little song we heard. Haven't heard it since.

Not too long afterwards, while i was still living with my brothers in the same house, another incident occurred. I was upstairs in my room, and it was probably around midnight. I had turned off my Xbox and TV, and was just laying in bed on my phone in the dark, when my pup started lightly growling. My dog is pretty smart, friendly, and really perceptive. He doesn't growl at anything unless he perceives a threat. He is always chill and silent throughout the night. But that night, he went from chillin' in bed with me with his head on my chest, to instantly sitting upright, intently staring and growling at a spot on the wall to my right. I didn't think much of it right away, and just tried to calm him down, but he just got more rigid and starting growling a little louder, still stating at the one spot. I sat upright, turned on my lamp, and looked around the wall to see if I saw a bug or a small critter, but there was nothing. He suddenly starts darting his eyes around that same wall as if he was following something that was moving quickly. All of the sudden, he whips his head and darts his eyes to a spot maybe 5 ft above my head. I look immediately above me, and see nothing at all. I felt an insane feeling of dread, grabbed my dog and ran to my brothers room across the hall, and asked if I could spend the night with him. I was way too fucking scared to go back to my room that night. Nothing like that ever happened again.

Not sure what either of those, and things like that don't normally happen to me. Which is probably why it's so scary to me. I don't think I believe in ghosts or demons or anything like that, but idk what to think of these instances. Could've been nothing, or could've been something I can't see/perceive. The thought of the latter scares me.