I don't have a clue, Audrey. I've often wondered what makes the pups scared of certain things. It always seems like some of the strangest things too. Katie has always been nervous around the sweeper but I kind of understand that one. I mean its loud and it moves...lol. Lately though it seems to be a game with her. She hops back and forth wooing and barking at it. I think she realizes now that it won't hurt her.