Urusei Yatsura 4: Lum the Forever

うる星やつら4 ラム・ザ・フォーエバー

Strange things begin happening in Tomobiki Town...

When a great cherry tree, "Tarozakura" is cut down while Lum & Co. are making a movie, Lum loses her horns-and her powers! Thus begins the strangest and most lyrical of the Urusei Yatsura movies...

(Source: AniDB)