This 8-inch Mega Grow-Egg Dino will grow into a dinosaur over 20 inches long! How? Place the egg in cold water and wait 24 to 48 hours. Then the eggshell will crack and the dinosaur will grow. Make sure the water level stays above the rim of the egg. Even if the dinosaur has fully hatched from the Mega Grow-Egg Dino, leave it in cold water until it's fully grown... and then you'll have a new dino friend!