Spoiler alert.
This documentary is such an intimate and immersive glimpse into the mindfulness of a female octopus, and the friendship that ensues between her and Foster, the diver (although I think the "friendship" was sort of one-sided on her part). The octopus came to know this guy, reached out to him, but in the end, when she's reached the end of her life span, he basically forsakes her. She's weak and dying, but instead of holding and letting her die in peace, or at least protecting her from the little sea creatures that come to eat her alive, he just watches. I found it very cold. Maybe I'm just not capable of retaining the objectivity of a scientist, but visiting this octopus brought him so much joy. You'd think he would have shown more compassion.