Expandable water toy

Common card · No. 420255

Expandable water toys (also grow-in-water toys or grow monsters) are novelty items made from a superabsorbent polymer. They are toys that expand after putting them into water for anything from a few hours up to several days, depending on size. They shrink in saltwater or when exposed to air. They are made from polymers that can absorb and retain extremely large amounts of a liquid relative to their own mass.

Read on Wikipedia · Image John Blyberg, CC BY 2.0