a while after my cat passed i started seeing black smudges (color of my cat) moving on my periphery, always kind of scared me and then made me sad.
someone also passed away in my house, specifically in the room i used to live in. sometimes it would get really cold, but i think that was the house, one time i looked over my shoulder in that room and thought i saw a really distorted and blurry humanoid shape in the corner of the room for a brief moment.
after many years the room started to become swarmed by flies, i sealed off every crevice and crack they could come from and still they would spawn in, i ended up moving out of the room and it stopped happening, never happened since.
i don't believe in ghosts i just think it's fun to pretend.