Mega Dinosaur eggs that hatch. Grow Egg will surprise your kids when they hatch because it comes with Different Dinosaurs inside! Imagine how excited your child will be when they await for the Prehistoric surprise creature to hatch and grow over a few days! It will teach them patience and commitment. Amaze your child with this set of Hatchin' Grow Dinos. Just submerge the dino egg in cool water and do not disturb for 48-72 hours. During this time, the dino will break out of its shell and the dino will begin to grow. After 48 hours, move your dinos to a larger container to watch them get bigger and bigger. Fully grown dinosaurs reach nearly 10" high.