I was playing Minecraft on a server and a weird thing happened when I started placing netherrack on the roof of my house. I heard ominous sounds I hadn't heard before so I decided to run inside for safety. When I got to the door it started opening and shutting repeatedly. When I got inside the house a stone block appeared in the room and slowly broke down to nothing and the music stopped. I went back outside and found a burnt looking music disk on the ground, C418-11. I played it and confirmed it was the sounds I was hearing.
So, I'm wondering is this a normal way to get C418-11, is there a spooky mod that is doing this, or did someone with special privileges go invisible, play the music, and then prank me?
I've tried placing more netherrack around with no effect.