Waterfuls were plastic handheld water filled toys by Tomy. They came in various shapes and sizes, typically smaller cylinders and larger rectangles. The basic was a ball catch, but themes ranged from sports - basketball, soccer, ring toss, fishing and many more.
They were filled with water through the top. The player squeezed a button, forcing air through the water. This made a wave/bubble to create the action, moving small plastic pieces / balls / fish etc. trying to get them where they needed to land.