They come in the night.
The only way that you know they have been is when you come into the office the next day, and notice that things on your desk are just not quite where you left them. The phone headset is dangling off the edge of the desk. The paperweight has been moved. The puzzle ball has had a piece knocked out, and you have to remember how to put it back together again. Nothing ever seems to be stolen, or actually broken – yet.
Some have a theory that the visitors are real people – that they are cleaners. There is no evidence to prove this theory. Things are no cleaner. Like other items on the desktop, any visible dirt has just been rearranged, not removed.
No-one has ever seen one of these mythical creatures. All we have is the evidence that they have visited in the night, and departed, leaving only the enigmatic evidence of their passing…