We don't have any cats or other animals that will snitch an object or two, but some of my items will disappear and re-appear in strange places. The other night I was looking for one of my favorite thimbles. I was sure I had put it in my traveling sewing basket, but couldn't find it. So the search began, found the gift card I was looking for a few weeks before, under a bunch of fabric, and the sand-paper circles to put on my rulers to keep them from slipping I found hanging on my bulletin board where I put pictures and new patterns I buy. But the thimble was no where to be found. Finally gave up and went to bed - woke up at 3am, started looking again for an additional 45 minutes, went back to bed and got up went back to my sewing room, got the other 2 thimbles and decided I must have lost it. Then opened my sewing basket, picked up the mechanical pencil to put it in the holder and there was the thimble.
So I do believe there is a gremlin or poltergeist living in this house. I would have accused my DH of playing a prank on me, but he does not go into my sewing room unless it is to put something on a table and walk out. He doesn't have a clue to what I do in there. He doesn't even take DVD's in and out.