Submerge the 4.5in dinosaur egg in water for 12-24 hours and watch the dinosaur hatch. Fully-grown dinosaurs reach nearly 12in size! Assorted dinosaurs. 5yr + From tiny egg to towering T-Rex, it's a magical mystery ride of awesomeness! And with an array of dinos to choose from, you can hatch a different dino every outing. Expedition anyone?