There seems to be a recurring theme in Japan of primates driving would-be tree-octopuses back into the sea. I've already covered tree-dwelling hominoids called Kijimunaa that guard the mangroves of Okinawa from the constant threat of octopus invasion, and monkey military retaliations against forest-melon-raiding octopuses, but here's an example on a much larger scale...
In Toho Studios' King Kong vs. Godzilla (1962), a really giant octopus named Oodaku (or Oodako; in Japanese 大ダコ, "giant octopus", or 海魔, "sea devil") crawls onto the shore of Faro Island and into a palm-shaded village in search of the natives' supply of soma berry juice.
(While the size of the octopus strains credulity, this desire to go into the trees for delicacies is common to most accounts of semi- or proto-arboreal octopuses, including ones from Spain [pickled fish], Greece [olives], British Columbia [chewing gum], and Oceania [pandanus flowers]. So points to Toho for scientific accuracy here.)
Thanks to sketchy intellectual-property-rights management, King Kong lives on Faro Island. Kong hears the commotion and comes out of the jungle to fight Oodaku:
Oodaku seems to get the upper tentacle by wrapping himself around Kong's head:
But eventually Kong is able to break free and force the octopus' retreat into the ocean.
Kong then drinks the soma berry juice himself and takes a nap, allowing him to be captured by a team from a pharmaceutical company headed by a wacky TV show host named Mr. Tako (literally Mr. Octopus -- Kong defeats one octopus only to be captured by another). Kong is taken back to Japan where the movie's titular battle occurs.
Here's a fan-made trailer with a few quick snippets of Oodaku vs. Kong at 0:54 and 1:28 (sorry, best I could find online):
The scenes with Oodaku were filmed with a combination of four live octopuses, either composited with the actors or on a small model set (as seen in the second and third photos above); a stop-motion model; and a large puppet (when battling the guy in the Kong suit).
Oodaku again appeared in Toho's Frankenstein Conquers the World (1965), in which Nazis take the immortal heart of Frankenstein's Monster to Hiroshima, where it's seemingly destroyed in the atomic bomb, only to turn up years later in a feral boy who grows to Godzillan proportions and fights a giant, fire-breathing dinosaur named Baragon.
In an alternate ending, giant Frankenstein is defeated by Oodaku, who drags him underwater. Unfortunately this was not included in the released film and was apparently only shot at the insistence of the film's octopus-loving financial backers, but it was included in later video releases. Here's some stills that give a better look at Oodaku:
Oodaku's final appearance was in War of the Gargantuas (1966) where he briefly fought Gaira, the green gargantua, at sea. Consistent with the anti-tree-octopus attitudes of the Japanese, each movie seemed to put poor Oodaku further and further away from the trees for which he so longed.