My two year old has a new obssession with spiders. "mommy, scary spider" when there is nothing there. I think it's just an active imagination as a few weeks ago it was dragons and bears. It could very well be something as simple as dry skin that is itchy, and she is worried about bugs in general right now. I always think things of concern are worth having her parents mention it to the Dr. , but I doubt there is anything serious going on.
When I was little I used to play with ants. When I went to bed I always felt like ants were crawling all over me, even though there weren't any. I think it's just one of those things that you dread so your imagination runs away from you. I wouldn't worry about it unless it became a chronic problem or you saw her behaving in other odd ways. Since it was just once I wouldn't think twice about it!
How old is she , you know we hear of children having imaginary friends and even imaginary animals ..I never think that there is anything wrong. Does Family even you encourage it, would she still do it if it got no attention.It is common for children to seek attention in any way possible , has she any siblings ?Does she do this when she is at school /daycare or in anyone elses house?