I think it would be a few years ago.
I was sitting on my bed late at night, and out of the corner of my eye I saw this white orb, about the size of a baseball, zip across my floor. I then heard tapping noises behind me, and the noise kind of traveled along my wall. Then I saw a massive shadow creeping up my wall and slowly disappear into the corner.
A few minutes later I stood up, and in my carpet where the orb had been, there was a perfect footprint that was way too small to have been my own.