The video shows a large marine lizard swimming underwater. The lizard has a long tail and is dark in color. It is swimming near the bottom of the ocean, where there are rocks and plants visible. The water is clear, and the sunlight is shining through, creating a beautiful underwater scene. The lizard moves gracefully through the water, its body undulating with the motion of its tail. The video captures the lizard from different angles, showcasing its size and the unique features of its body.