Marshall Fine has called Tim Blake Nelson‘s Leaves of Grass a “textbook example of a promising movie that takes a wrong turn from which it never recovers. Starting well, building good will, assembling a solid farce framework, Nelson’s script suddenly abandons all the comedic promises it makes in the first half and turns into a blood-drenched and sadistic action film.

“It’s like grafting the last half of Death Wish on to a stoner comedy (which, come to think of it, describes the similarly uneven — but much funnier — Pineapple Express).”

I didn’t like Leaves of Grass either, but tone-shifting can be a profoundly cool move. One of the finest, nerviest and neatest films of the ’80s — Jonathan Demme‘s Something Wild — pulled a major attitude-switch toward the last third when Jeff Daniels had to grim up, fierce up and put Ray Liotta down like a mad dog. I for one worshipped Demme’s decision to turn his light and quirky relationship comedy into Cape Fear.

I’m trying to think of other successful examples besides Wild and Pineapple. Need a little help.