Start with "I imagined" and finish the story.

I must have imagined the sound coming from my bedroom.  No one was at home with me, I had no pet to make that unearthly yowl which I had just heard, and I was not going to entertain the idea of the supernatural.

Nope.  Not going to even think of the supernatural.  Drat!  I'm thinking about it, suspecting it, even starting to fear it now.

I crept down the hall from my living room toward the pitch dark bedroom flipping on lights as I went.  I came to the spare bedroom which I use as an office and flipped on the overhead light.  White light immediately filled all the darkened shadows in every corner, and I took a mental inventory.  My laptop sat on my desk buried in student papers.   I was supposed to be grading essays, not trying to debunk the supernatural tonight.

Feeling a little better, I turned from the office and continued down the hallway.  I got to my bedroom and stood in front of the closed door.  My heart was racing.  I NEVER shut my door, why should I?  I lived alone and had no reason to shut it.  Breathing hard, I touched the doorknob and slowly turned it pushing the door open.

As the light from behind me flooded into the blackened room, a loud howl of agony ripped through the air.  My skin erupted into goose bumps, and I hunched back away from the door.  What was in there?

I jumped forward and hit the light switch just inside the doorway.  I froze, eyes wide, mouth open and ready to scream, fists bunched and ready for a fight.  

Nothing.  

The room was empty.  

I felt a cold breeze across my face, and I my thoughts jumped back to the supernatural. I'd heard spirits trying to manifest sucked the energy out of the air and left cold spots. 

This was bad!  I was going to have to move.  I couldn't afford to move!

I gathered all my courage and stepped into the bedroom.  The curtains moved in the window, I braced myself for the worst, and crept forward to investigate.  I reached out to the yellow, flowered curtains and felt the breeze increase.  The window was open a few inches.  

Of course!  I remembered cracking the window this morning after my shower to let out the warm humid air that had filled the adjoining bathroom.  The breeze and cold air were easily explained now, and the door probably closed from the draft.  

I was relaxing and feeling pretty proud of myself for not running out screaming earlier like a big baby until I remembered the horrible scream I had heard earlier.

I reached out to the window and was about to close and lock it when the howl shattered the quiet evening again.  I jumped back, but I saw something on the outside of the window.

I stepped cautiously forward and peered out of the window.  There on the window ledge perched a small, black cat.  The cat dangled with the claws of one paw stuck in the window screen.  Its wide green eyes frantically met mine through the screen, begging me to help.

Quickly, I opened the window fully and used my fingers to push the cat's claws back through the screen to the outside, and he, or she, pulled its paw down onto the small window ledge.

"There you go, baby," I whispered.  Poor kitty.  I wondered how long it had been stuck outside the window.

The cat gave me one long look of what I assumed to be gratitude, jumped down to the grass below, and disappeared into the night.