Doraemon: Nobita and the Legend of the Green Giant

Doraemon the Movie Nobita and the Green Giant Legend , Eiga Doraemon Nobita to Midori no Kyojinden? , is an anime film that was released in Japan onMarch 2008.

Nobitas troubled about what to do with his zero test marks once again. A gust of wind scatters his test papers and he falls into a garbage dump trying to gather them together again. There he finds a young withered tree that caught one of his papers and he decides to take it home. He tries to plant it in his garden but gets caught by his mother who doesnt allow him to grow it.Still wanting to keep it but not being allowed to grow, Doraemon comes up with the idea of making it come alive with a gadget he uses. Nobita names the little tree Kib because all it can say is ki. As the days pass, Nobitas parents also accept Kib because he was a very smart boy who helped Nobitas mother whenever he was away. However, aliens from the Planet of Green decides to pass judgement claiming humans were destroying all the green on Earth. Nobita and his friends manage to escape by coincident and arrive at their planet. They are warmly welcomed to their city of Green Pier but also learn of what they are doing to their planet. ........

Source: Wikipedia