“Deadpool,” starring Ryan Reynolds as a debauched comic-book superhero/assassin who’s like Spider-Man crossed with the Phantom of the Opera crossed with Jim Carrey, is a movie the whole world was waiting for without knowing it: a Marvel franchise caper that runs on drop-dead attitude. In the opening credits, the camera glides through a freeze-framed car crash (the men in the vehicle are at each other’s throats, and maybe a few other body parts), the whole suspended orgy of destruction set to the mocking romantic strains of “Angel of the Morning.”

The credits then proceed to thumb their nose at 1) Reynolds’ Sexiest Man Alive cover for People magazine; 2) the filmmaker, Tim Miller, whose credit reads “Directed by an Overpaid Tool”; and the entire superhero genre. The movie hasn’t even started yet, and already it’s deconstructing itself like Mad magazine crossed with a Geico commercial.

The air of nihilistic nonchalance extends to the main character, Wade Wilson, a maimed Special Forces killer who is antic, edgy, and maybe a little nuts.

Clad in dirty Spandex, wielding twin ninja blades that he uses to slice up his foes like a Benihana chef, Wade delivers his verbal fusillades with the fey wrecklessness of someone who doesn’t care if he lives or dies (“I only have 12 bullets, so you’re going to have to share!”).

Yet the grungy beauty of “Deadpool” is the way that Ryan Reynolds — and the entire movie — invests not caring with bombs-away conviction, a quality that turned out to mean more to audiences than the mark-hitting franchise joylessness of such films as “Captain America: Civil War” or “Suicide Squad.” For a while, it even looked like “Deadpool” might be the first movie to break the Academy Awards’ superhero cherry and nab a best picture nomination. Alas, it was not to be. Hollywood likes its awards films with a twist. But not this twisted.