This article contains Ant-Man spoilers, so if you want to avoid those, I advise to check something else out in the meantime.
If you don't care, then carry on.
The current ending of Ant-Man has Michael Pena's character, Luis, inform Scott that an Avenger is looking for him via one of his "tip" scenes, hopping from person to person like a game of telephone. The ending is one of the very few instances where a Marvel movie ends on a humorous note, but that was not the original plan.
Cinemablend spoke to director Peyton Reed about at the Los Angeles premiere, revealing it had involved Martin Donovan's Mitchell Carson.
"At the end of the movie he gets away and has these Cross particles, and there was a sequence where Ant-Man has an encounter with him," Reed explained. "But then for a couple reasons, it felt like maybe we should leave those particles out there. In that original thing, he took Martin Donovan out and got the particles."
So the Cross particles, the more sinister version of the Pym particles, are still out there, waiting to be used again in some fashion. Maybe an episode of Agents of SHIELD will address the issue?
What do you readers think? Think we'll see the use of the Cross particles down the line?