Abstract: A weight-adjusted underwater toy is disclosed having a somewhat lower specific gravity than water, and having its center of gravity located below and somewhat behind the volumetric center of the toy. The toy has a streamlined shape, like a fish, a sea animal, a swimmer, or a submarine. The model will follow a long glide curve similar to an approximately upside down ballistic path when flung into the water, and will always rotate into a position with its back up and its abdomen down. When rising, the location of the center of gravity will provide an inclined forward/upward position for the model, and horizontal side wings (fins or other details) will prevent a purely vertical rising movement by providing a forwardly directed momentum during a buoyancy movement.