Put one product into water, the  animal will grow when it is in water. As other life-forms which were born from eggs, the animal grows up from an egg step by step. This product imitates the progresses of biology's birth, and is educational. This product has passed authentication, and is safe, non-toxic. There are kinds of poses of the crocodile, and they are mixed packing. This product can grow up to 600% of its original, and can be kept in water for a long time.