Cujo & Me

 The really terrible thing about it is that it is basically "The Oval Portrait" -

And he would not see that the tints which he spread upon the canvas were drawn from the cheeks of her who sate beside him. And when many weeks bad passed, and but little remained to do, save one brush upon the mouth and one tint upon the eye, the spirit of the lady again flickered up as the flame within the socket of the lamp. And then the brush was given, and then the tint was placed; and, for one moment, the painter stood entranced before the work which he had wrought; but in the next, while he yet gazed, he grew tremulous and very pallid, and aghast, and crying with a loud voice, 'This is indeed Life itself!' turned suddenly to regard his beloved:- She was dead!

- in which there is no painter and no art, and the happy couple - red faced, "better for having gone through the tribulations of an incorrigible pup", ready to pop out a few of their ghastly blond brood - sup young canine life together.

The portrait they paint is naught but that of themselves as relationship, weeping and consoling each other over the picked bones of their finished meal.

Proposed sequel: At the beginning, during a lightning storm, Marley claws his way back out from the front-yard grave.  The rest of the film basically follows the plot-line of Cujo.