Hemiclepsis marginata, a diminutive leech. When disturbed, it has the remarkable ability to curl into a compact ball resembling a pill bug, measuring about 8 mm in diameter. This defensive behavior enables it to roll freely down slopes or be carried along by water currents. Sporting four eyes, arranged closely in two pairs, it displays distinctive reproductive behaviors: adults bearing green eggs beneath their bodies tend to remain motionless in a protective stance, while those without eggs are notably more active. Its natural hue is a greyish-green shade, but under bright sunlight, it can take on a vibrant yellow or brownish appearance.