10 Greatest Unspoken Sci-Fi Movie Plot Points
2. Agent T's Wife & Kids - Men In Black 3
Men in Black II is far from a great movie, but it does tee up an amusingly long-gestating secret subplot which pays off quite incredibly in the third film released an entire decade later.
In MiB II, Agent J (Will Smith) is paired with the well-meaning but incompetent Agent T (Patrick Warburton), resulting in J eventually kicking him out of MiB, neuralising him, and setting him up with a cute waitress at the diner (Alexandra O'Hara).
J suggests that T should get married and have a couple of kids, and lo and behold, in Men in Black III's altered timeline, J encounters a woman in K's (Tommy Lee Jones) apartment with a husband and a few kids - the woman also being played by Alexandra O'Hara.
The obvious wink-wink implication is that, in this timeline, Agent T did indeed marry the waitress and start a family.
Even though the man seen in the back of the woman's apartment clearly isn't played by Patrick Warburton - who presumably wasn't available? - it's still an ingenious slice of fun quasi-continuity between sequels.