My Octopus Teacher (2020) was co-written and co-directed by Pippa Ehrlich
and James Reed.
It stars Craig Foster and a female octopus that lives in the frigid waters at the southern tip of South Africa. (Craig's son, Tom, has a small role.)
After Foster finds the octopus, he visits her den every day--literally. After a while she becomes accustomed to his presence, and appears to accept him as a companion. (It's very difficult to avoid anthropmorphism when watching a nature film. However, I was convinced that there really was two-way relationship between the human and the invertebrate.
For the record, I don't usually enjoy nature films. I liked this one because of the interaction between human and octopus. (It's the same reason I like Bronx Zoo--it's as much about humans interacting with animals as it is about the animals themselves.)
My Octopus Teacher has a strong IMDb rating of 8.2. I agreed and rated it 9.
P. S. My close friend told me I'd like "the octopus movie." I dutifully looked for that movie, and found a science-fiction movie about a giant octopus that could entrap and sink huge ships. This movie is not that movie.