Nils no Fushigi na Tabi (Movie)
English title: The Wonderful Adventures of Nils Movie
Japanese title: ニルスのふしぎな旅
Alternative titles: Nils no Fushigi na Tabi, Nirusu no Fushigi na Tabi, The Wonderful Adventures of Nils: The Film, Wonderful Adventures of Nils (Movie)
Type: OVA
Source: Novel
Episodes: 1
Status: Finished Airing
Aired: Oct 1, 1985
Duration: 1 hr 36 min
Rating: G - All Ages
Studios: Pierrot
Genres: Adventure, Fantasy
Demographics: Kids

Nils Holgersson is a young boy on a farm who is cruel to the animals. But when he catches the farm's little goblin it becomes one prank too many. He is magically shrunk and suddenly the farm animals are out for revenge. He flees on the back of the goose Morten and they join up with a flock of wild geese. Together they travel all over Sweden, with Nils hoping to find a way to become big again. 

(Source: ANN) 

Note: No theatrical release was actually made and it became available to the general public as an OVA in 1985.

(Source: AniDB)