Pool Manta - it "flies" underwater

grabcad

In a manner reminiscent of an airborne glider yet reversed, the Pool Manta "flies" through water as buoyancy causes it to ascend. To initiate its journey, place the manta at the pool's depths and observe its lifelike swimming motion. The tail propels the manta forward or backward, altering its center of gravity and thereby controlling its speed - a frontward weight shift quickens its ascent towards the surface with a splash, while a rearward shift induces a slow climb to the top. A balanced weight distribution results in side-to-side jerky movements. Invert the manta, and it will perform a flip before surfacing right-side up. Rotate the tail for directional changes, while adjusting the top fin's pivot controls the manta's trajectory - a slight pivot ensures straight swimming, while a more pronounced turn results in circular paths around you. This product has been personally tested and used in my own pool, confirming its functionality beyond theoretical assumptions. However, take note that ABS material is susceptible to degradation under sunlight exposure, necessitating the Pool Manta's removal from the pool when not in use, or sealing it with high-resolution printing or acetone application for waterproofing.