In January of 2000, our family dog died. My family had been living in this house already for about ten years, with never a strange occurrence. About two months after the passing of our beloved pup, while home alone during the day, I heard heavy footsteps upstairs. So I actually went upstairs to look and see if I had an intruder on my hands (silly me, I didn't even bring a weapon - I'd be sure to be the girl in the horror flick that runs upstairs instead of outside!) This house was huge, and I did an attic-to-basement search, even going so far as to check inside closets and under the beds. Now, as soon as I got to the stairway to go up, the footsteps stopped. Finding nothing curious, I returned to the living room and continued watching my TV program. About three minutes into this, the footsteps started again. So this time, thinking that somehow the intruder had eluded me, I snuck up the stairs quietly again, nothing. I once again settled on the couch, and from then on just ignored the footsteps that sounded whenever I was home alone during the day. Oddly enough, they never sounded at night.
Not too long after this started, I began to wake up in the night to see a shadow man stand in the corner of my bedroom, watching me sleep. Naturally it scared me, but when it never approached, I'd just go back to sleep. I'd never felt threatened by any of this, until one night I woke up to the sound of someone sneaking around in the attic (which was right above my room). After a while the noise stopped, and I snuck to my door to make sure that the attic entrance (one of those ceiling pull-doors) was closed. It was. I tip-toed back to bed, and went back to sleep after a while. When I woke up the next morning, my light fixture was disconnected from the ceiling and was hanging from the electrical wire!
I always kind of thought that while our dog was alive, she kept the spirit (s) away, although she'd never exhibited signs of seeing "others", and when she passed, they were then permitted to make themselves known.