Basic Trope: A character challenges another with the phrase, or some variation of the phrase, "You and what army?" An army then shows up.
Straight: Bob challenges Alice to stop editing a trope entry. Alice asks "You and what army?!" Bob points to a legion of tropers as they march over a nearby hill with Torches and Pitchforks, and says "That army!"
Exaggerated: It literally is an army; tens of thousands of people with embedded support, helicopters, artillery, armor, all to stop Alice from editing TVtropes.
Downplayed: A small group, such as the TV Tropes administration team, shows up.
Justified: Bob knew Alice would not be easily convinced without a superior display of force, and made sure he had an army beforehand.
Inverted: The army retreats.
Subverted: Bob says "That army!" and points to empty space. The army doesn't show up, having run off when he wasn't looking.
They come back.
They hadn't run off, they were just invisible.
The army was stalled so they do arrive, but just a little later than Bob had planned.
Parodied: A good number of gun barrels/blades are put up to the characters' neck midway through their attempt to say the phrase.
Zig Zagged: The army doesn't arrive... but then it actually does, after a fair bit of time. But then, the newly-arrived soldiers realize it's lunch time and call a break.
Averted: The phrase isn't used at all, or there is no army.
Enforced: "We need a moment to bring in The Cavalry and people have seen it already, write it in."
Lampshaded: "Where were you hiding all these guys?!"
Exploited: ... and uses it to wipe out Alice, Bob and Bob's army all in one fell swoop.
Defied: Alice realizes Bob is about to call in his army, so simply keeps him talking, making it seem as if he might very well convince her to stop without having to call them in. Then she finishes her edit and runs.
Discussed: "Dude, you probably should have told me he was an army general before you let me say that."
Conversed: "You know, is there ever any actual time when someone says 'You and what army' and it just ends there?"