It's an Orange Aardvark! by Michael Hall
Summary from Amazon:
Five carpenter ants at home in their tree stump hear a noise. What is it? One ant thinks it is a hungry aardvark lurking outside the stump, just waiting to eat them. One ant makes a hole in the stump to see. Orange light floods the stump—it's not an aardvark, proclaims the ant chorus. It's orange! So what is lurking outside the stump? This very funny picture book features die-cut holes on almost every page, suspenseful page turns, a wonderful surprise ending, and an introduction to a rainbow of colors.
You are looking at the tree stump from the inside where the ants are:
As each new hole is drilled, a new color of light shines in: