It has been theorized that species of tree octopuses around the world originally took to the land, and eventually the trees, in search of tasty vegetation, such as ara flowers, tree pitch, and olives. The Japanese have a similar theory: octopuses came into the forests in search of monkey melons. Unfortunately for these would-be tree-octopuses, the monkeys fought back.
In Manzo Miyashita's 1936 animated short, お猿の艦隊 (Osaru no Kantai or The Monkey Fleet), an army of octopuses comes out of the sea and into the forest to steal watermelons from rifle-armed monkeys. The monkeys shoot at them, but the octopuses' superior numbers and incessant advancement allow them to overrun the monkey militia and reach the melon farm, where they take all the melons they can carry back into the sea.
The monkeys regroup and organize a retaliation by launching a fleet of tiny, single-monkey steamships to destroy the octopuses in their lair. But when they arrive the octopuses use spring platforms to hurl themselves up at the undersides of the ships, knocking the monkeys off. Undaunted, the monkeys send an S.O.S. signal to summon their submarine fleet.
The octopuses take shelter in a cave as one lone octopus guards the entrance with a sword. The monkey-subs shoot torpedoes at the octopus, but he manages to slice the torpedoes in half, spitting the occasional one back at the subs. Eventually the barrage of torpedoes becomes too much and the octopus squirts ink and retreats into the cave. A monkey-sub follows and blows the cave up with a torpedo, sending an explosion of octopuses flying everywhere. The monkeys then do a little underwater dance. The End.
The whole action-packed story plays out in a mere minute and eight seconds. Unfortunately, if you want to watch it legitimately, you'll have to shell out over US$120 for the 4-DVD set Japanese Anime Classic Collection from Digital Meme or wait until there's another public showing. [UPDATE: If you're in L.A., the Japanese American National Museum is showing it and other classic anime on August 4th @ 7pm.] It's not on YouTube any longer. [ANOTHER UPDATE: here's some more stills.]
What with these blood-thirsty monkeys and the kijimuna, it's no wonder Japan has no native tree octopuses.