Single-Issue Landlord

"Open up in there! I know you're hiding a cow!"

The often comical combination of Cranky Landlord, Nosy Neighbor and Single-Issue Wonk, this is a landlord who is obsessed about one extremely specific clause in the rental contract of his tenant. With this obsession in mind, he will proceed to hound said tenant relentlessly thinking that one day, he will at long last prove that the tenant is breaking the rules and therefore evict him.

Of course, most of the time the tenants are breaking the rule—the landlord is only just dumb enough that he can't actually prove it. The viewers, by contrast, are well aware of this and laugh at what a buffoon the landlord is, as the intended result of this device is Hilarity Ensues.

Because of the obvious silliness inherent in this trope it never really caught on—it remains with us in pop culture today largely as parody.

Note that despite the name, this trope is more about the situation than the actual landlord—and that there could be consequences for the exposed Masquerade besides just losing a place to live.

Film

 * Cruella De Vil doesn't care about how she does it as long as she evicts the Dearlys from the farm but one of her attempts included proving they had more animals than the number allowed by their contract. (101 plus the farm animals)
 * Mr. Shickadance, Ace Ventura's landlord, does not allow animals in his apartment complex. Ace, of course, has a whole lot of animals at his place, though he hides them quite cleverly.
 * Not a landlord, but in the Curious George movie, the Man in the Yellow Hat has to hide George from his building's doorman.
 * Green Card: Guy and girl have to pretend to be in a relationship so she can get her dream-condo (which is couples-only), and in return he gets the titular Green Card. Somebody suspects that they're faking it, and Hilarity Ensues as they have to keep the tangled web of lies from collapsing. Needless to say, they wind up actually falling in love.
 * Laurel and Hardy's short Laughing Gravy. Laughing Gravy is a small dog, and once again the landlord doesn't allow pets.

Live Action TV

 * In Bosom Buddies, the main characters had to pretend to be women.
 * The cITV series Emu has a landlord that doesn't allow pets. Unfortunately for Emu, he's an emu.
 * In Spaced, the two main characters are pretending to be in a relationship in order to rent a flat for a couple,
 * The Trope Maker is Three's Company. Its reputation as being a fountain for Idiot Plots is largely based on the only part of the show anyone remembers—that Jack has to pretend to be gay so the landlord doesn't realize the apartment is a den of sin. You'd think Janet and Chrissy would just avert this entire conflict by getting a female roommate, but it would seem that Jack's cooking really is that good.

Theater

 * In Love, Sex, and the IRS, the landlord is obsessed with catching the main characters breaking his no female visitors policy. The play is about the two male roommates pretending one of them is a woman so they can cheat on their taxes by claiming to be a married couple. Hilarity Ensues.

Video Games

 * Parodied in Sam and Max Freelance Police Season 1, where the heroes are forced to audition for "Midtown Cowboys", a show where the titular cowboys must hide their herd (of one cow) from a landlord who constantly suspects that they're hiding a cow in their apartment. Featherly's Tagline is the page quote.
 * The Tagline of the sitcom itself deserves recognition, both for being an Expository Theme Tune and stupidly catchy. You wouldn't think the single line "They're probably hiding a cow!" could even be MADE into an Ear Worm, but the evidence suggests otherwise.
 * The announcer from Monday Night Combat will sometimes plug a show called "Meat the Meatsacks", a family of humans who pretend to be cyborgs so they can stay in their apartment.

Web Comics

 * Parodied in a strip of Penny Arcade with "That's So Locust", a show about a Gears of War alien that must pretend to be a human woman for the purposes of this trope.

Western Animation

 * On one Looney Tunes short, Tweety and Sylvester are being hidden by their respective owners in a hotel that doesn't allow pets. At the end, the manager asks all tenants to get rid of any animals in the premises... and is trampled by a whole zoo's worth.
 * On The Roman Holidays, Mr. Evictus was determined to prove that Gus Holiday had a lion in his family's apartment.