Yeah, those imaginery friends...Casper and Kitty sure have them, and we call them 'little men'. For no apparent reason they may attack the wall, or punch the floor or just attack something. We can't see anything there, so we come to the conclusion: little men...They both also like to stare things that don't excist, like a wall that is completely white, but yet, they make it look so exciting, that we have to go closer and have a look, if there's something in there. And of course there isn't . And they also love to pretend to be playing with something on the floor, and when we go and look at with what they're playing, we find out that it's nothing (unless they're punching those little men of course, little men are invisible to us ).

Such creatures are cats...can't ever understand them (and hey, maybe that's better that way )