Oh, shoot. Running time: 110 minutes. Rated R (for violence and language). Now playing.

I’d rather wake up next to a severed horse head than ever watch “Gotti” again.

The worst movie of the year so far, the long-awaited biopic about the Gambino crime boss’ rise from made man to top dog took four directors, 44 producers and eight years to make.

It shows. The finished product belongs in a cement bucket at the bottom of the river.

Keeping this mafioso mess alive throughout all the turmoil has been John Travolta, playing John Gotti. Travolta, who’s made a career out of Italian stereotypes, obviously thought the Dapper Don would be his Don Corleone. It’s his Chef Boy­ardee.

In one scene, he yells “whatsamattayou?!” and slaps one of his minions. In another, after John “Junior” Gotti starts a bar fight where a guy winds up dead, Travolta screams, “You ­c–ksucker! This is gonna ruin your life!” and again slaps him in the face.

His performance is a leather-faced freak show. And the plot is nonsensical.

The film bounces between 36 years of events seemingly at random and with the flimsiest of context. Call it “Whack to the Future.” We move from 1979 to 2009 to 1983 and back to 1979. We meet Frank DeCicco, ­Angelo Ruggiero, Sammy Gravano and about a million more mobsters who we never learn anything — or care — about. We move from Massapequa to Little Italy to Queens but rarely see the same place twice.

Just two events are clearly presented: The 1980 death of ­12-year-old Frank Gotti by a car and the shooting of Gambino boss Paul Castellano outside Sparks Steak House in 1985.

The rest is an excuse for ­Travolta to shmact and for his wife, Kelly Preston — playing Gotti’s wife, Victoria — to howl like Medea.

As Junior, Spencer Rocco ­Lofranco is OK. He, at least, thinks through his role instead of rabidly twitching like Travolta. But he’s also 25 and appears 17. While Junior’s being indicted in 2009, Lofranco looks like Macaulay Culkin’s parents forgot him in a courtroom.

Kevin Connolly was the final director on this project, so he gets saddled with the blame. His flick is ham-handedly edited, stylistically incoherent and Travolta’s Hallmark-card narration is more confusing than helpful.

It’s the worst mob movie ever, but I see a bright future in midnight showings. “The Gotti Horror Picture Show.”