Spidey Gets an X-Men Assist in 'The Amazing Spider-Man 2' Credits Scene

Marvel heroes of the world, unite!

Everyone knows by now that a superhero movie ain't over till it's over, and that means waiting until the very end of the credits to catch a last-minute bonus scene. And so it goes with the arrival of the summer-launching "The Amazing Spider-Man 2" — but we don't get a teaser for a future wall-crawler adventure or spinoff. Instead, the mid-credit sequence is from a rival comic book property from a rival studio, Fox's "X-Men: Days of Future Past."

Sony, which produced the Spidey sequel, confirmed to Yahoo the hero linkage after the sequel opened in the U.K. Wednesday and word began to spread online of the unusual promotional crossover. But American audiences will have to wait for the film to open on May 2 to see it on the big screen.

"Yes, there is an 'X-Men' coda during the closing credits of 'The Amazing Spider-Man 2,'" a studio rep said. "As you know, moviegoers have come to expect a coda on many of their Marvel films, and they're often disappointed when there isn't one. We saw this as a win for fans and audiences everywhere as it's the next Marvel movie out of the gate."

Empire was among the first outlets to report the inclusion the "X-Men" scene, which features a clutch of mutants working their X-powers in a large-scale battle sequence:

"The scene featured sees Jennifer Lawrence's Mystique, Lucas Till's Havok and Evan Jonigkeit's Toad taking on William Stryker (Josh Helman) and his military men. Without wishing to spoil anything, let's just say that Mystique once again demonstrates her formidable fighting skills in the brief segment."

According to our cohorts at Yahoo UK, the "action-packed sequence" seems to take place during the Vietnam War and ends with a plane taking off.

[Related: Final 'X-Men: Days of Future Past' Trailer: Wolverine Gets Mutant All-Stars Together]

The addition of the clip appears to be recent: the early critics screening of "Spider-Man 2" did not include the "X-Men" scene.

Meanwhile, there is also a teaser for future Spidey adventures in the closing credits, but Sony kept the details sketchy.

"The entire credit sequence is a coda of sorts," the studio publicist says, "opening with a virtual schematic created to tease comic book fans regarding what's ahead for them in the Spider-Man universe." Sony already has two villain-themed spinoffs in the offing, "Sinister Six" and "Venom."

[Related: The Daily Bugle Hints at Villains for Future 'Spider-Man' Spinoffs]

While rival studios might form uneasy alliances to help snag Marvel-sized audiences, there's no chance Wolverine or Magneto (or the Fox-owned Fantastic Four) would ever make an appearance in an actual Spidey movie as long as three different studios control the separate Marvel properties (Marvel parent company Disney handles the third piece of the puzzle, the Avengers and related characters in the so-called "Marvel Cinematic Universe").  So fans will have to remain content with three studios building expansive franchises around their distinct collection of licensed characters.

According to Variety, the unusual cooperation between the studios came about as part of the contract negotations with the film's director, Marc Webb. Webb was under contract with Fox after previously making "(500) Days of Summer," and as a stipulation for him signing onto the "Spider-Man" sequel, Sony agreed to a free promotion for the new "X-Men."

This kind of cross-studio promotion isn't a new thing. The opening scene of "The Dark Knight Rises" (2012), a Warner Bros. project, was attached to Imax prints of Paramount's "Mission: Impossible — Ghost Protocol" when it hit Imax theaters in 2011. Seeing the dastardly doings of the villainous Bane on the large-scale format inspired some advance ticket sales, as "The Dark Knight Rises" broke Imax records with a $19 million opening weekend.

"The Amazing Spider-Man 2" opens in U.S. cinemas on May 2; "X-Men: Days of Future Past" hits May 23.