I remember when I was a lot younger, I had this pet hamster that died partly due to neglect... basically he'd chewed through one of the rungs on his ladder then got his head trapped in it. I didn't check him that often so by the time I found him there, he was dead. I felt pretty guilty.

Anyway, we cleaned the cage out etc. but left it in my room. One night when I was struggling to get to sleep I heard a noise like someone running their finger down the metal frame of the cage. "brrrriiing"

I was convinced it was the hamster haunting me because I could have saved him. Needless to say I moved the cage away & never heard it again.

To this day, I've no idea what could have caused the sound. I was prone to sleep paralysis then which can cause hallucinations but still, I'll always think it was the hamster.