The Malacopods are the 3rd Largest phylum on Kerbin, with over 50,000 described species. These animals are often found in aquatic environments. Not many Malacopods have entered the land, but they have done so during the Karbonian. Like most other animal phyla on Kerbin, Malacopoda emerged during the Kerbian Explosion, around 510 million years ago.  They were the most dominant marine animals during the Orbian and Siadorian periods, their numbers dwindling during the Cryonian period, because of the Cryonian mass extinction event. They have risen to prominence again during the Tyrannic periods, which saw a global cooling and increased aridity after the Thermonian mass extinction event. The Malacopods may have been superseded by the Kerbinian fish as the main megafaunal marine animals, but they are still prolific, and some can grow to huge size

The Malacopods are quite distinct from the similar phylum Gastrocerebra. Both phyla consist of soft-bodied organisms, with radula-like mouth parts. Where they differ, however, is mostly whether they have shells and whether they are mostly aquatic or terrestrial. Malacopods have orange eyes with cross shaped pupils. These work like Kerbal vertebrate eyes, but can see more and weirder colours. Many Malacopods also have shells, which are an ancestral trait, with many Malacopods internalising their shells, turning them into internal skeletons of sorts. Many Malacopod bodies are shaped in a similar fashion to Earth's Cephalopods, with some resembling Chitons.

Many Malacopods inhabit the vast oceans of Kerbin, serving many niches alongside the marine vertebrates, occasionally coming into direct competition. Many Malacopods are also benthic, spending most of their time on the seafloor, preying on marine Kerbarthropods, Anapods, Pidakapods, and other Malacopods. 

Deep Sea Kraken

The Deep Sea Kraken is the 2nd largest complex animal on Kerbin, after the Dreadnoughtocetus. As mentioned in the Dreadnoughtocetus section, the two animals are fierce rivals, competing for the supremacy of the oceans. 

The Kraken is about 35 to 40 metres long, with a diameter of it's head tagma measured at around 5 metres. It has long and powerful tentacles, which are used to manipulate food items and other objects. These tentacles are also flexible, covered with sharp spines close to and at the tip, which can be used for extra grip. the eyes of the Kraken are as wide as a Kerbal is tall, making them the largest eyes of any animal on Kerbin. These eyes have at least 10 different cone cell types, as well as being able to detect circularly polarised light, and also IR and UV radiation. The  Kraken eyesight rivals that of some marine Kerbarthropods. Their beaks are unusually bird like. Attached to powerful base muscles, they are exceptionally strong, able to shut in half a second, and generating a bite force of 13,000 psi, crushing any prey the Kraken might catch.

The Kraken, despite its size, is incredibly fast and agile, reaching speeds of up to 50 mph in short bursts and around 40 mph for extended periods. It is also fairly intelligent, along with others of its kin, and able to use tools for especially hardy prey. The brain of the Kraken and its sister species is complex, working like that of an octopus. The Kraken also has a large, hard, mineralised shell, made up of calcium carbonate and other minerals. This shell is dark green in colour, as the Kraken inhabits deep waters of Kerbin.

The Deep Sea Kraken is an opportunistic omnivore, able to eat anything it desires to maintain its caloric need. A Kraken may be able to clear a small swathe of sea life in a single meal. Meat makes up around 70% of its diet, but marine plants are also on the menu. However, the most delicious delicacy, in the mind of a Kraken, is a Dreadnoughtocetus calf. But these are hard to come by, as the Dreadnoughtocetus tends to travel in herds. Likewise, a Dreadnoghtocetus may feast on a Kraken baby, whose mother may protect it, along with dozens of siblings.

The Deep Sea Kraken has a somewhat cosmopolitan range, with individuals spread across most seaways of Kerbin. The Loveheart ocean has barely any Kraken individuals, as its warm waters don't really allow for the Kraken to hunt normally, as it prefers cooler water. The Kraken are also quite territorial, with many individuals only tolerating their offspring, and even then for a short while. This is because food at their desired living space is quite scarce, and the Kraken has a adjustable metabolism to compensate. This means that social behaviour among Krakens is rare, and the only social interactions that some individuals may have is when breeding. When breeding, two Krakens court each other for a few days. In the final moments of this period, the actual copulation takes place, during which a male will use one of his arms to deposit a packet of sperm into a female of his choosing. He will also give her some food, be it a fresh kill or some gathered shore-life or something else entirely, to use for herself and the offspring. Once fertilised, the female will consume the departing male's gift. After a few days, she will lay around a hundred eggs, which hatch within a few weeks. The Kraken larvae are small, red and initially dependent. The mother will feed them with a translucent grey goop, containing important nutrients. The young feed on the goop for a short while, the mother caring for them for a few months before they are able to fend for themselves and leave her protection. A Deep Sea Kraken can expect to live for 45 years.

The Deep Sea Kraken got its name from legends told by Kerbal sailors during the Exploration period and subsequent periods of history. These stories describe the Kraken attacking ships as they sailed treacherous seas. Such attacks were rare, as the Kraken was unwilling to consider a Kerbal ship as a worthy meal. If an attack did occur, it either because it was desperate, or it was bored. Many Kerbals across history have seeked to exterminate the Kraken, using whatever means possible. This caused these attacks to increase, as the Krakens began to do so in self-defence. Eventually, after countless studies, and due to advancing ship design, the Kraken started to be seen as a respected part of its ecosystem, instead of a monster that should be destroyed. Nowadays, the Kraken is not seen as a problem... with one exception. There is one particular legend about the Kraken that lives to this day. There is a supernatural Kraken that likes to hang out in space, destroying spacecraft for fun.  The unexplained nature of this elusive being, known as the Deep Space Kraken, is an additional reason why space flight is so hard for Kerbals, as it strikes occasionally.  For this reason, the Kraken has become a feared cultural icon, appearing in books, movies and other media.  It its rumoured that the Deep Space Kraken being is the descendant of a Deep Sea Kraken.