SPOILER WARNING: If you haven't seen "Ant-Man" yet, then read no further. There be lots of spoilers here.

We all know how Marvel rolls by now: the movie ends, then during the end credits we usually get two short (but fun) scenes.

"Avengers: Age of Ultron" broke this long-standing practice earlier this summer, but "Ant-Man" brings it back in a big way. In fact, it's last end credits scene comes from a different Marvel film entirely: "Captain America: Civil War."

That's a big deal; it's the first time Marvel has used a scene excerpt this way from one of their other films. In fact, the Russo Brothers ("The Winter Soldier") directed the scene, which Kevin Feige decided to use for "Ant-Man" instead of what was planned, a more comical scene, according to an interview with iO9.

So what does this scene entail? Here come the SPOILERS:

After the first end credits stinger (no pun intended), which features Hank Pym (Michael Douglas) showing an upgraded version of the Wasp suit to his daughter, played by Evangeline Lilly, we drop in on Steve Rogers (Chris Evans).

Cap is out of costume, moving stealth-like toward a man whose face we can't see -- with his arm confined by some device. The man looks up, and it's -- drum roll, please -- Bucky Barnes (Sebastian Stan), aka The Winter Soldier. This scene clearly takes place after the events of "Winter Soldier," where we last saw Cap and fellow Avenger Falcon taking off to find Steve's best friend-turned-HYRDA assassin.
Where this scene occurs in "Civil War," however, remains to be seen. (We assume early-ish in the film; think before the start of the second act.) Joined by Falcon and with Bucky in custody, it becomes a question of: what do we do now and how do we get our cargo out of here?

Cap quickly shoots down Falcon's suggestion to contact Tony Stark for help, implying that the disagreement they had while chopping wood in "Age of Ultron" has boiled over into "Civil War." (Duh.) Also not an option? Calling in the New Avengers, last seen posing for their close-ups at the end of "Ultron." (Why they can't call on them isn't quite clear, indicating that either Cap is going full broken arrow here with this side-mission, or that most of those team members have sided with Tony in the pending conflict between allies.)

As they weigh their options, Falcon gets an idea: "I know a guy." And yes, that guy is Scott Lang/Ant-Man, who we last saw duking it out with Falcon when Lang broke into Avengers HQ during his solo film.

So Lang will play a significant role in the events of "Civil War," seemingly enlisting on the side of Team Captain America (for now). Also, this scene establishes that the events of "Ant-Man" run very closely to those of "Civil War," perhaps both films occur within a few months of each other.

With Lang on the ground floor of "Operation: Breaking Out Bucky," that also sets up the possibility that Winter Soldier will have a role in the pending war between the Avengers. Is he Team Cap or Team Stark? Will his super-killer programming pit him once again against his best friend?

We'll found out when "Nerd Christmas" "Civil War" hits theaters May 2016.