In the OP6, Kogarashi Sentiment (木枯らしセンティメント), of Monogatari Series: Second Season, there are a red crab and a white snake. Since:
At about 0:57 of the OP, there is a shot where the snake wraps around the crab, which seems to be a metaphor of the intimacy between the two MCs and may even indicates that she's more aggressive in their romantic relationship. (ready to eat/bite the crab?)
It's obvious that then crab is a metaphor for the male MC and the snake is a metaphor for the female MC. (Of course, there are more witnesses of this, but a complete list would make the post tedious.)
In the spirit of this interpretation, let's see what are in the last 2 scenes. In the 2nd last, the female is falling down when she explodes into some snake-like threads. In the last scene, the white hat of the female MC falls by the side of the red crab. These seem to indicate that in the end of the story, the female MC left the male MC (maybe due to death or something like a doomed fate), and he becomes lonely again, missing her.
A few questions about the story induced by the interpretation:
- Are the two MCs separated in the end of the story? What separates them?
- Is the female MC the first to make a move in their relationship?
- Are they by any chance nonhuman, maybe actually a crab and a snake?