Achaeus japonicus, commonly known as the orangutan crab, is a small, fuzzy crab often found living in association with bubble coral in tropical Indo-Pacific reefs. Covered in fine reddish-orange hairs that resemble an orangutan’s fur, it uses this camouflage to blend into its surroundings. Despite its tiny size (around 2 cm), it's a favorite among underwater macro photographers due to its unique appearance and shy behavior. The hairs also trap debris and plankton, aiding in feeding and disguise.