Rent-A-Zilla

In a movie about ghosts, they throw in this.

A work is not about Kaiju or other giant monsters, but it throws them in anyway because of the Rule of Cool.

Godzilla, or some Lawyer-Friendly Cameo, is a common choice, of course.

Can overlap with Attack of the 50-Foot Whatever, if the small thing turned huge is sufficiently monstrous (and of course not the focus of the work), and is often the result of Make My Monster Grow.

Compare Instant Awesome, Just Add Mecha, Instant Awesome, Just Add Dragons.

Examples of Rent-A-Zilla include:

Anime & Manga

In A Certain Scientific Railgun when the Level Upper network of 10,000 espers went out of control a giant growing fetus-monster-thing made of ambient psychic power spontaneously appears and starts rampaging around Academy City (which is located right next to Tokyo). The randomness of this is lampshaded when it randomly starts heading for a nearby nuclear power plant.

Mikoto: Am I in some kind of Kaiju movie?

- No events in the series explain how this happened, but events in the parent series A Certain Magical Index imply that this was not quite so random, and was in fact a Call Forward to the creation of the Fuze=Kazakiri artificial angel.
An episode of Mythical Detective Loki Ragnarok had a shrine statue turned into one when imbued with a lot of dark magic.

Comic Books

Red Ronin and the boozy father monster from Top Ten seem kinda... odd.
Marvel Comics also has a Red Ronin, a Super Robot created to fight Godzilla; it becomes a rent-a-zilla after that series when it is used in comics such as The Avengers.
Preceding all the other "Animated Lincoln Statue" references in this page: An issue of Captain America (comics) from the 1970s had him attacked by the statue after it was animated by the telekinetik villain Animus. Yes, Captain America battled Abraham Lincoln.
And, once again, the statue of Abraham Lincoln (well, Abraham Linkid) comes to life in an issue of Captain Carrot and His Amazing Zoo Crew.
The giant rampaging Abraham Lincoln at the beginning of TUA:Dallas

Film

The Stay Puft Marshmallow Man from Ghostbusters, and the second film had them using positive ghost slime to turn the Statue of Liberty into one.
The statue of Abraham Lincoln comes to life near the end of Night at the Museum II and fights the bad guys.
Austin Powers has a scene where a giant inflatable T-rex is unmoored and goes careening down the street, at which point two Japanese bystanders start up this conversation:

First guy: RUN! It's Godzilla!
Second guy: It looks like Godzilla, but due to international copyright law, it's not.
First guy: Still, we should run like it is Godzilla!
Second guy: Though it isn't. (Winks at the camera.)
(Both run off screaming)

Dude, Where's My Car? starts out with two stoner dudes looking for their car, but ends with them running from a giant alien babe.
In Shrek 2, Shrek storms the castle with the help of a giant gingerbread cookie named Mongo.
The 1950s Toho film The Mysterians, a film about aliens, has two brief scenes involving a giant robot named Moguera.
- Likewise, the 1962 film Gorath features a brief scene where the heroes fight against a giant walrus (Yes, you read that right) named Maguma. Interestingly enough, the dub of the film removes this scene since, well, it has nothing to do with the main plot of the film.
In cult comedy director "Savage" Steve Holland's film One Crazy Summer, inspired by childlike wonder and curiosity, actor Bobcat Goldthwait dons a costume which bears a striking resemblance to, but is never specifically referred to as one of the Giant Rubber Monster incarnations of Godzilla. When he is unable to remove the costume after a lit cigar is thrown into the open mouth of the suit, he goes on a terror-driven rampage (coincidentally destroying a scale model of a proposed housing development in the process, mouth smoking all the while, to Godzilla-like music) to the delight of the attending Japanese investors.

Literature

The second book in The Secrets of the Immortal Nicholas Flamel gives us the Nidhogg, who starts out as an oversized Komodo Dragon but soon begins walking on two legs like Godzilla and smashing buildings and cars in Paris.

Tabletop Games

Magic: The Gathering: During the Dissension tie-in novel, Ravnica is attacked by giant monsters. First there's some Nephilim that grow giant-sized and start smashing things, then the Izzet's dragon guildmaster Niv-Mizzet flies in to fight them off, and eventually Experiment Kraj and Rakdos the Defiler join the fray as a result of a Gambit Pileup. Widespread destruction ensues.
The Tarrasque in Dungeons & Dragons is not in any way, shape or form lifted from Godzilla. None whatsoever.

Video Games

One level in Psychonauts has the player character as a giant rampaging through a Tokyo-like city of fish people.
This trope gets a fair bit of mileage out of Honest Abe, it seems: The first season of Telltale Games' Sam and Max series has an episode in which the Villain of the Week converts the Lincoln Memorial into a giant robot that claims to be the reincarnation of the original, to run for President when the previous robot president is "assassinated" by the famous duo.
One scenario in the original SimCity has a Godzilla-like monster attacking Tokyo in 1961. This monster is replaced with Bowser in the SNES version.

Webcomics

Name comes from Megatokyo, where there was a service called this. In addition, there was a rampage by The Alcoholic uncle of the Gamera family.
Sluggy Freelance has used a couple (not counting all the ones during the Voltron parody). There's the Crudosaur as well as one of Aylee's transformations.

Western Animation

The South Park episode "Super Best Friends:" David Blaine brings the statue of Abraham Lincoln to life and it rampages across Washington DC. It's subdued by a giant stone John Wilkes Booth.
- And the "Mecha Streisand" episode.
- Don't forget Mickey Mouse suddenly and inexplicably growing to large size and destroying Denver with his firebreathing powers in the Jonas Brothers episode.
In a Simpsons "Treehouse of Horror" episode giant advertising mascots come to life and terrorize the town
- In another episode, they go to Japan; when they leave the pilot makes the following announcement:

Uh, folks, we're experiencing some moderate Godzilla-related turbulence at this time, so I'm going to go ahead and ask you to put your seatbelts back on. When we get to 35 thousand feet, he usually does let go, so from there on out, all we have to worry about is Mothra, and, uh, we do have reports he's tied up with Gamera and Rodan at the present time. Thank you very much.

Ultra-Peepi from Invader Zim
The Fairly OddParents: Timmy accidently wishes one up through sleep wishing.
Dexter's Laboratory: Dexter and Mandark bring Abraham Lincoln and George Washington to life, using their heads off Mt. Rushmore. Giant Abraham Lincoln is almost a subtrope in and of itself.
- Also, in the half-hour episode "Last But Not Beast", an axe-themed Kaiju Monster of the Week appears, and the majority of the episode is spent dealing with it.
- Another episode has Dexter and Dee-Dee mutating themselves into bigger and bigger monsters.
A Gojira Captain Ersatz shows up in Teen Titans: Trouble in Tokyo, along with other Japanese cultural stereotypes.
From the Animaniacs episode where the Warners do "Jack and the Beanstalk" (along with a parody of "Green Eggs and Ham"): Would you, could you, in Japan, with Godzilla and Rodan?
Star Wars: The Clone Wars has them accidentally awaken the massive Zillo Beast in one episode and bring it to Coruscant the next, with predictable results.
Rugrats had the in-universe Reptar, a child-friendly Brand X knock-off of Godzilla.
Pinky and The Brain had one named "Gollyzilla."
The Season 1 finale of Avatar: The Last Airbender featured Aang and the Ocean Spirit fusing into a spectacular, Godzilla-esque One-Winged Angel (nicknamed "Koizilla" by the fans and creators) to defeat an enormous fleet of Fire Nation ships.
The monsters in Yam Roll mostly exist as an excuse for Yam Roll to use his superpowers, or to give him more opportunities to make passes at Minamiko.
The Smurfs: In "Papa's Big Snooze", the Smurfs have to cross a lake inhabited by a monster fish called 'Carpzilla'.
101 Dalmatians the Series featured a literal example when Cecil B. de Vil borrows the "Choc-zilla" animatronic from his studio to attack the Dearly farm.