adult play. Conversely, the water absorbing collapsing waterball or waterbag is generally caught with one hand. Because it collapses on impact on the water or in your hand, it is easier and safer to play with young children ages 4+. A sealed ball displaces and bounces on water as it interacts with the water surface. On impact with the water surface or a player's hand, the sealed waterball deforms and deflects and transfers its energy in the opposite direction as it bounces on impact. But a sealed waterball no matter how soft still maintains its spherical shape and ball like properties. The fluid dynamics and shape characteristics are relatively unchanged as the sealed waterball does not change its density. As such, even tennis balls and handballs, stress balls can be used as waterball and perform, admitted poorly, depending on force and angle to the water etc. Water absorbing waterballs or technically "waterbags", on the other hand, are designed for water and density exchange. Water freely permeates the whole ball, adding more weight and dynamic fluid density. The added weight makes this type of waterball skip and roll on water, rather than bounce. As a result, water absorbing high-performance waterballs travel shorter distances than sealed waterballs but they are easier to control and play with both in long and short range. A waterbag exchanges its fluid density and transforms and conforms its shape and fluid contents on impact with a surface or plain. On impact with a surface such as water, the waterbag dissipates its energy dynamically as it interacts with the water surface exchanging fluid contents. This changes and balances the bag's density, mass and shape to conform to the water or surface it is performing on as it loses its velocity and comes to rest. The beanbag-like design of the waterbag changes shape and conforms to a surface thus it collapses and is "slow acting" on impact. There is a significant difference between the physics of the sealed waterball and the water absorbing waterball or waterbag. The waterbag exchanges its fluid contents on impact and it changes its shape as it collapses on impact. There is no bouncing or minimal bouncing action. Slow acting on impact is an intended design characteristic that is very pleasing and safe in high-speed play action. The "rolling action" of the waterbag that is referred to a "low skip profile" on the water surface