The Sims 2: Pets Easter eggs

Rock Ridge Fossil!
Have you ever noticed how some landscape items like trees and rocks fade in half when you look through them? Well seems like theres an easter egg to do with it!
Use your Sim and go to the north part of the area, you should see a very large rock. Move your sim to the left of the rock and make him/her look too the right. Now move the camera so its looking at your Sim through the rock. You will see a fish fossil!