This could be made into a sweet story, although it's a bit sad:
Octopus moms are a good example for altruism in the animal kingdom as they sacrifice themselves for their babies.
A female octopus lays about 100,000 eggs and fastens them to the ceiling of a den. Without protection the eggs would be eaten by predators or become diseased, so she stays in the den and guards them. She caresses the eggs with her tentacles to ensure that algae don't grow on them. Also she constantly keeps the water moving around them to provide the eggs with enough oxygen. It takes the eggs 6 months to develop before they hatch. During all those months the octopus mom cares for them and doesn't leave them for one moment, which means it prohibits her from hunting for herself, so she doesn't eat a thing. She gets weaker and weaker until, by the time the eggs hatch, she has nearly starved to death. (Apparently a few individual octopus moms have been observed eating their own tentacles, rather than leaving their offspring.) She then uses her last energy to blow her babies out of the den to help them on their way. Soon after that she dies because of starvation or because she is too weak to defend against predators.
Please let me know if there are any grammar (or other) mistakes, as English is not my first language. I used a few internet pages and youtube documentaries for the information. Leave a comment if you're interested in the sources.
Update: I didn't expect this post to become so popular, so here are the resources I used:
https://www.youtube.com/watch?v=3ehHQOziuF0 (this one shows the story really well :)
As I wasn't sure which pages would be trustworthy, I read all of the pages above and wrote down the facts they all had in common, so I hope the facts are right.