This has been done once by every sitcom and sitcom-like cartoon since 1952.
Alice and Bob are neighbors, and they hate each other. One day, Alice goes to a government office and finds a city map that shows her property extends well past the fence between them. Alice will begin commandeering anything of Bob's that falls into her property. A tree, a workshed, the TV in his living room, etc.
The episode frequently ends with Bob discovering that the first read it wrong, and what it really meant was that the property line cuts into Alice's property instead. Insert defeated "wah-wah-waaaah" trombone sounds here.
This is usually Snapbacked as it never comes up again.
Note that this is a classic example of Hollywood Law: in reality this kind of discrepancy would (1) immediately lead to a lawsuit, which (2) would almost always be solved by somehow granting Bob the land he thought was his. (The mechanisms here are adverse possession, which is basically a Statute of Limitations as applied to property law, if he or his predecessors in interestnote used the land consistently enough for long enough, and various kinds of easements and forced sales if he hasn't.)
- There was once an issue of Disney Magazine that had this happen to Donald Duck. He finds a bricked-up doorway in his cellar, behind which is a chest of valuable antique coins. He sells them, and goes on a spending spree, only to have his neighbour come by with a map proving that anything behind the bricked-up door is actually on his property. All of Donald's fancy new furniture is repossessed, and immediately re-purchased by the neighbour, so Donald has to make do with some old chairs found in the main part of the cellar. Turns out the chairs are even more valuable than the coins were.
- The Oscar-winning silent 1952 short Neighbours, directed by Norman McLaren for the National Film Board of Canada, is a dramatic and disturbing instance. A surreal anti-war parable, it depicts an escalating battle between two homeowners over the ownership of a single flower growing right on their property line. Watch it here.
- In the classic Polish comedy Sami Swoji two families end up in a Feuding Families situation because a Kargul plowed '3-fingers-width' deep into land claimed by the Pawlaks. The eldest Pawlak son retaliates by hitting the Kargul with a scythe and then flees to America. Decades later the two families need to cooperate to survive the aftermath of World War 2 but the patriarchs still occasionally break the peace when they get into silly property disputes over things like who owns the cat that hunts the rats in their sheds.
- A Serious Man: Larry is in a low-simmering dispute with his neighbor over their property line. The neighbor wants to build a boat shed across what Larry considers their property line. The neighbor begins to mow a strip of Larry's side of the lawn as a passive-aggressive way of asserting his own definition of their property line.
- Older Than Feudalism: The Bible prohibits moving your neighbor's boundary stone or other property marker, presumably to prevent just such a quarrel taking place.
"Do not remove the ancient boundary stone that your ancestors set up." (Proverbs 22:28)
- Subverted in the famous Robert Frost poem, Mending Wall, published in his Collected Poems. It isn't necessarily about the property line intruding on either person's side of the fence, but rather whether or not a literal stone wall is needed to solidify the property line.
"Good fences make good neighbors."
- Diary of a Wimpy Kid: Wrecking Ball: It turns out that an extension to the Heffleys' house is over their neighbor's property line, so they have to tear it down and patch up the hole in the wall.
- Night Watch Discworld: Sam Vimes alludes to this trope while musing on the difference between what the police can do and what people think they can do:
"Keep the peace. That was the thing. People often failed to understand what that meant. You’d go to some life-threatening disturbance, like a couple of neighbors scrapping in the street over who owned the hedge between their properties, and they’d both be bursting with aggrieved self-righteousness, both yelling, their wives would either be having a private scrap on the side or would have adjourned to a kitchen for a shared pot of tea and a chat, and they all expected you to Sort It Out."And they could never understand that it wasn’t your job. Sorting it out was a job for a good surveyor and a couple of lawyers, maybe. Your job was to quell the impulse to bang their stupid fat heads together, to ignore the affronted speeches of dodgy self-justification, to get them to stop shouting, and to get them off the street. Once that had been achieved, you job was over. You weren’t some walking god, dispensing finely tuned natural justice. Your job was simply to bring back peace."Of course, if your few strict words didn't work and Mr Smith subsequently clambered over the disputed hedge and stabbed Mr Jones to death with a pair of gardening shears, then you had a different job, sorting out the notorious Hedge Argument Murder. But at least it was one you were trained to do."
- Sanford and Son: "This Land Is Whose Land?" Fred gets a surveyor to measure his and Julio's property line so he can get Julio to keep his stuff out of the junkyard. It turns out Julio legally owns most of the yard.
- Married... with Children: In one episode, Jefferson D'Arcy takes an apple that fell from the Bundys' tree and Al argues with him over the apple's ownership. It leads the two families into finding out the official boundary between their lands isn't even a straight line. The tree belongs to the D'Arcys. The Bundys further research the map and find out the D'Arcys' barbecue drill is in their property. The D'Arcys retaliate by setting a toll booth at the Bundys' garage entrance. The Bundys retaliate by reporting an irregular improvement that, since it's done on what turned out to be D'Arcy property, the D'Arcys are fined for it. They eventually decide to make peace but then another apple falls off the tree and Al and Jefferson fight over it.
- That 70s Show - happened exactly like the trope's definition, starting with Bob taking things from Red's garage and ending with Red finding out that he owns part of Bob's house.
- The episode involving Lawsuit Fever in Doctor Quinn Medicine Woman involves Dorothy, who owns and operates the local newspaper, finding out that her property actually extends into the area where Grace has set up her cafe. This sets up a rift between the two friends, and they soon find themselves going to court over it. Since the original judge ends up not being able to get into town, Dr. Mike has to be the judge. She ends up ruling that since the commonly accepted property boundary has been assumed for so long—even when the newspaper office was purchased—the area belongs to Grace.
- The Bonzo Dog Band's song "My Pink Half Of the Drainpipe" explores this concept in song.
- In a second-season episode of The Flintstones, Barney painted a property line through the middle of the room Fred just added to his house (tricking Barney into doing all the work.)
- The Jetsons: This was the central plot point of the episode "Private Property"; Mr. Spacely had George examine the blueprints, where he believed that Cogswell's new building was 6 inches over Spacely's property line, until Cogswell re-examines the blueprints and finds that his property is the bigger one and Spacely's building was 6 inches over. Cogswell manages to talk Spacely into buying Cogswell's building, which George discovers is 6 inches too tall and has to be dismantled, only to find out that Spacely got stuck buying Cogswell's building which has to be torn down.
- Goof Troop, In the episode "Goof Under My Roof" plays it straight, when it looks like Pete owns half of Goofy's house, and he then claims everything in that half as his. At the end, it turns out that Pete doesn't own half of Goofy's property,. but rather Goofy owns half of his.
- A Mighty Mouse cartoon "The Green Line" featured a town where mice lived on one side of said line, cats on the other. An evil cat spirit tries to get the cats to ignore the line and attack the mice, but Mighty quickly arrives to restore peace.
- One episode of The Pink Panther ("Pink Panzer") had an unseen narrator building up conflict between the Pink Panther and his neighbor, starting with a couple of borrowed possessions, but then coming into this trope when he, at the narrator's urging, saws off a limb that extends over the line, dropping leaves into his yard. The neighbor retaliates by sawing off part of the Pink Panther's house that was extending into the space over his yard. The narrator gets the panther to build a wall, then the neighbor to bring out a unit of artillery, the panther to bring out something bigger, the neighbor to call in some military help... At the end, the narrator is eventually revealed to be The Devil.