These creepy guys are Skeleton Panda Sea Squirts, also known as Ascidians. Like all sea squirts, they are sessile, meaning that as adults, one end of the body is always firmly fixed to rock, coral, or some similar solid surface. The upper surface of the animal, opposite to the part gripping the substratum, has two openings, or siphons. When removed from the water, the animal often violently expels water from these siphons, hence the common name of “sea squirt”.
Almost all ascidians are hermaphrodites. The sexual organs are located in the abdomen or postabdomen, and include one testis and one ovary, each of which opens via a duct into the cloaca. Broadly speaking, the ascidians can be divided into species which exist as independent animals (the solitary ascidians) and those which are interdependent (the colonial ascidians). Different species of ascidians can have markedly different reproductive strategies, with colonial forms having mixed modes of reproduction.
Sea Squirts come in an amazing range of shapes and sizes, and reach anywhere between 0.5 and 10 cm tall (0.20 to 3.9 in). Some of them are even colonial, the more simple of which are individuals attached by a kind of root system while the more advanced may be physically fused together and form colonies several metres across.