I'll try to make this brief, for it only happened once. Why, I have no idea, for that’s how the inexplicable goes sometimes.
I was up late one night on the computer, doing the usual: surfing the net. I knew I'd better retire soon, but I was not worried about waking anyone when I did go to bed, for I slept in the basement (no floorboards to creak and groan), which was where the computer was as well.
It began at about 12:30(yes, all you night owls, that’s late for me!). I was telling myself I'd visit just one more site, when, from the first floor overhead, came a sound, a hum, very faintly at first: "h-h-hmmmmmmmmmm...."
Great, I thought, some jerk is running his car(we have noisy neighbors). Then as the humming got a bit louder, I decided it was not the sound of some distant motor. It sounded as though it were coming from the throat of a human being!
The weird part was that it was constant and never changed pitch, neither high or low. It got to the point where surely whoever (whatever?) it was would take a breath, but it remained steady.
Then it changed slightly, as though the hummer had opened his/her mouth. Now it was a steady, melodic "aaaahhhhhhhhhhhh". It reminded me somewhat of a choir warming up, save that it was a single voice instead of many. And it was quite a lovely sound, despite it sounding in my house in the dead of the night! Then it grew louder, and began to move.
Silly me, I still thought it was an actual person up to this point. Why, I don't know, since neither my sister or mother, the only other occupants of the house, were in the habit of late night humming. Then I realized that if someone WAS up there, their footfalls would cause the floorboards to crack, as we have a noisy floor. But the floor was quiet, the hum moved uninterrupted above my head, as though there was only the voice, nothing else.
I then wondered if the voice would come downstairs to where I was. At that point the first sliver of fear shivered through me. Lovely as the voice was, I had no desire to see who or what might be making it.
I could not move, however. A simple, terrible logic settled in my mind: What COULD I do? Run to my bedroom and hide under the blanket? How childish(I'm 25, after all)! But it was exactly what I intended to do, and was just jumping to my feet.... when the voice stopped.
For several moments I waited, listening. Nothing. I continued to wait. For about an hour I sat there (AOL eventually kicked me off due to inactivity).
Then I nearly jumped out of my skin, for another sound broke the silence.... right behind me! But this sound I knew: my 12-year-old kitty meowing. He rubbed against my leg, purring. I knew he was hungry, and in order to feed him, I’d have to go upstairs!
My cat ran up the stairs without any hesitation. If he had heard the hum as well, he must have either forgotten about by now, or sensed that it had gone. I trusted the latter and followed him. Sure enough, nothing was out of the ordinary. My other cat was sitting patiently by the food bowl as the first cat joined her. I fed them, went back downstairs, and went to bed. The rest of the night passed quietly and uneventfully. Despite myself, I fell asleep quickly.
The next morning my Mom (who, BTW, also sleeps in the basement) informed me that I had woken her up in the middle of the night, when I came down the stairs, which creak, too. However she made no mention of the strange hum.
I never heard the midnight hummer again, mainly because I go to bed a lot sooner now, and I plug my ears tightly!