The video shows a close-up of a sea creature, possibly a sea slug, crawling on rocks covered in green moss. The creature is black and has a long, slimy body. It moves slowly, undulating its body as it navigates the uneven surface of the rocks. The water is clear, and sunlight filters through, creating a dappled effect on the rocks and the creature. The video captures the creature's movements in detail, highlighting its texture and color contrast against the vibrant green moss.