Eyeballs - A Concept

The above is a screenshot for a concept for my interactive toy.
How it works:
. When you click the left mouse button an eyeball appears where the mouse was.
.The longer you hold the left mouse button the larger the eyeball will be.
.As you move the mouse around the screen the eyeballs will look towards the mouse.
.If you move the mouse faster so the eyeballs follow it faster they will become agitated and their colour will change from what started as a serene blue (maybe) into a violent red.

In this there are two interactions, the placement of the eyeballs and the movement of mouse so that they follow its gaze.
I think that both interactions are interesting enough to hold a persons attention for a certain amount of time, when the person has figured out what it does there are still new possibilities of placement and size that can be created and therefore the user is more likely to play with it for longer.
I think that if it were just a geometric shape being created it would be rather boring, but because they are eyeballs they are creepy enough and bizarre enough to be enjoyable to arrange and explore.