I went through a phase when I was about 8-10 years old of imagining my two Action Men coming to life at night. Quite scary at the time, I was convinced they were out to get me. I think it was the size of them - Star Wars figures presented no threat, I could easily squash them but Action Man seemed to be about a foot tall and I'll have only been about 4ft myself. Plus they had weapons.
They were kept in the bottom of the wardrobe in my bedroom, all jumbled up with their jeep and helicopter and of course when the house cooled down at night, there would be strange noises of them shifting about. Sometimes in the daytime I would creep up on the wardrobe and quickly open the door, expecting to see them alive, plotting against me.
(I don't know what use this was apart from to scare myself even more.)
Later, I would guess I was 11 or 12, I would sometimes be left alone at my Granny's house during the day while they went shopping. She had a large collection of figurine ornaments and I would get freaked out sometimes just waiting for them all to move and look at me.