Octapodi
First of all there are 3 main characters in okatapodi. An orange and pink octopus and a man appearing to be a fish monger. The two octopus seems to like each other but on the other hand the man wants to sell the pink octopus.
The pink octopus gets put in the truck and drives off but the orange octopus jumps on to the truck in attempt to help the pink octopus. Near the end the orange octopus manages to save the pink one but after that the orange one gets caught by a seagul. I think that in the end both octopus will end up in the sea.
This movie is probably set somewhere in the mediterranean since there were many white houses.
Mermaid
The relationship between the mermaid and the boy is slightly peculiar since the mermaid is only seen by the boy. It's in his imagination. The boy lives in a place where imagination is not allowed and goes through a series of problems with the police. Finally the boy looses his imagination and is not able to see the mermaid again. But at the end when the boy goes to the sea with police in the background, a mermaid appears in the distance.
When the boy went to the sea I think the boy wanted to commit suicide since he lost his imagination. At the end mermaids do appear in the sea but no one will speak of it because they might be imagining something.