Akkorokamui is an ancient water-deity from Japanese folklore, myth and theology - as a deity it was both respected and feared, especially given its particularly violent origin and unpredictable nature: it is envisioned as a massive octopus of truly titanic properties, which measures in the hectares and is said to be able to swallow whales and ships whole.. when the deity rises it turns the sea itself red and for this reason ancient mariners would not set sail when they saw the tide turn this color.
Akkorokamui was originally a giant spider named Yaushikep who lived atop a great mountain, red in color and measuring at least a hectare the monster descended upon a nearby village and his movements shook the very earth itself, terrifying the villagers.
Unable to fight such a monster the people called out to the gods for aid and the sea god, Repun Kamuy, acted on their prayers by dragging the monster into the bay where it was transformed into a gigantic octopus and given a new role as the deity of that particular bay.
While no longer a rampaging beast the now-divine creature will still try and capture any who stray too close and thus mariners who have no choice but to sail near the deity's known lair equip themselves with scythes to try and ward of its assaults, those who do not face a risk of a watery demise.
While a deity the tale of this octopus is similar to many other stories across the world, such as the Kraken (though originally the Kraken was not actually an octopus in design as the ancient Norse saw it more as a crab or lobster).