At first, I thought it was cute movie, but it has some important message.
Main character is the creature like a rabbit.
Setting
The events happen in an imaginary world such as field probably in the future.
It fights against the industrialization by human.
Climax
The jellyfish saved the animal's society and purified the environment.
Symbol
Jellyfish is the symbol of cleanness. In fact, the body of jellyfish is transprant and clear.
Irony
In fact, the world where animals live was in the body of jellyfish.
Theme
Don't destroy the environment. Our earth is not only for us but also for animals.