An Ixulova Tun (lit. "large, unliving spirt person") is a zombie-like creature of old Low Rostran lore which would eventually become the namesake of a unique class of dieseltech auto-armor available only to the Rostran Archipelago Confederacy.
An ixulova tun is a large, humanoid mass of shambling necrotic flesh and catamaran parts which is animated by the vengeful spirits of mariners contained within its mass. Because of the vagaries of the Iuxat, places (including seafaring vessels) are talked about as though they 'possess' things in their vicinity. For example, if something is to the stern of a ship, it is phrased as if it belongs to the stern, which, in turn belongs to the ship. As such, when a crew is located on or within a ship, they are said to belong to the inside space which belongs to the ship. Should a ship sink, then, they are still possessed by the vessel even in death. This possessed state might prevent them from easily returning to the spiritual cycle, as presented by the local Esotericist beliefs, unless a proper search is conducted for them or the proper funerary rites observed. Desperate to escape this purgatory, the tortured spiritual amalgam of dead crewmen and ship - for even objects have spirits in the eyes of the Esotericists - might rise from the ocean to exact bloody revenge on impious coastal villages.
While the ixulova tun is manifestly a mythical being derived from traditional, animistic folk beliefs, it likely also came about as a post-hoc way of explaining the destruction and carnage which would be found when a tropical storm or tsunami completely wiped out coastal communities. Rostrans, like humans, are wont to seek out some sort of reason behind otherwise senseless tragedies, and these sorts of natural disasters would often leave no survivors to tell the tale. Alternatively, some tales of ixulova tun might have come about as a respons to ovinex slave raiding along the coasts in the Rostran-Ovinex War antebellum period. A large body of muscular ovinex warriors ripping into structures and clobbering the people inside with ba'amba might leave similar devastation in a coastal village to the attack of some massive zombie hewing into the village with bits of shattered catamaran rigging, but it's hard to know for certain.
The fear of ixulova tun has caused the cannon of Rostran Esotericism to expand with regard to the rites performed for mariners lost at sea. While modern Low Rostrands regard ixulova tun as a colorful mythological diversion at most, others see the ixulova tun as a metaphor for the need to respect the danger of the sea and remain faithful to those who cross its waters - even should they never return. To this end, heirophants still often perform warding rites at the coastline during low tide, as the Ixaba indicates that certain sigils, when drawn in the sand at low tide, can prevent an ixulova tun from making landfall.
Ixulova tun are frequently portrayed in Rostran horror films as unthinking, unstoppable monsters which represent the fury of a tempestuous sea, though some recent movies have instead portrayed them as stalking, nocturnal predators from the deep.