擁有堅硬外骨骼與短腿的甲殼類生物，常見於海岸或潮間帶的石縫與沙地。能蜷曲身體以防外部衝擊，主要食用海藻與腐敗有機物。迅速移動以避開陽光與浪潮，發揮著海岸生態系清潔工的作用。
A crustacean with a hard exoskeleton and short legs, it is discovered between rocks and sand on the beach or tidal flats. It can curl its body into a ball to avoid external shocks and mainly eats seaweed or decaying organic matter. It moves quickly to avoid waves and sunlight and serves as a cleaner in the beach ecosystem.