To make your own dinosaur eggs, gently crack the egg just enough to that you can get your finger nail in and chip a hole.  Put a knife in and cut the yolk.  This will help you get the egg out easier.  Once the egg is out wash with hot water then set aside until completely dry.  Paint the area around the opening with clear finger nail polish to give it strenght.  Paint the egg with a base coat then seal with clear finger nail polish.  Next use crackle nail polish to paint the egg.  This nail polish will go on smooth but start to crack all over the eggs after just a few seconds.  Seal the egg and you are finished.  If your dinosaur has a long tail you may want to make a small hole in the back so that the tail will stick out.