There is indeed a kind of pearl that can absorb water and become bigger.
Really?
Sea baby is a colorful bead. Soak in the water for five or six hours, and actually "grow up" a hundred times. It feels soft and elastic. This kind of "toy" called "sea baby" has been especially popular with children in recent years. The main components are acrylonitrile and acrylate, which are toxic and harmful to children's skin and respiratory tract.