Hatchin’ Grow collection comes the popular Ginormous Hatchin’ Grow Dino Egg. Each 4.5-inch speckled egg comes in its own colorful box and dissolves in water to reveal 1 of 4 assorted dinosaurs inside. Submerge egg in water for 48: 72 hours to dissolve. Assorted dinosaurs include a T. rex, parasaurolophus, triceratops, and stegosaurus.