Also known as: ウォーターシップダウンのうさぎたち, watershipdown, Watership_Down
A 1978 British animated film, based off the book of the same name.
Controversial in that it was aimed at children (it was rated U by the BBFC, equilavent to a G rating in America and Japan, though it actually got a PG in America), and yet it's quite disturbing.