Anthropomorphic Zig-Zag

This is like a standard Anthropomorphic Shift, except the shift is geared to the role or co-star a character is in a work, movie, short, cartoon, or episode. For example, an animal character appears as an Nearly-Normal Animal in one cartoon or episode, but appears as a Funny Animal in another.

This trope also includes examples that shift roles back and forth in a single work or shift back and forth depending on their mood. There are also a lot of characters do this intentionally to live a double life, going from walking on two legs to Running On All Fours depending on the company. The shift can either be intentional or unintentional.

The difference between a Anthropomorphic Shift and an Anthropomorphic Zig-Zag is that the former is what happens when animal and anthropomorphic characters in a work become progressively more human-like in appearance and behavior in later installments. The latter is a shift dependent either on the role or co-star the character has in a work or roles he/she has in a single work or his or her mood, or to live a double life.

This trope is by no means restricted to animals.

Furry Reminder is a related trope, as is Furry Denial.

Film

 * In Madagascar, the animals would constantly go back and forth between walking on four legs and walking on two legs.
 * Remy and the other rats from Ratatouille can switch between walking on two legs and walking on four legs too.
 * Remy walks on two legs to keep his forepaws clean.
 * This is also true with the Pizza Planet truck from Toy Story, which was later seen in anthropomorphic form in the Pixar film Cars.
 * The three paintings, one of Lightning McQueen, one of Doc Hudson, and one of Flo and Ramone, make those four Cars characters look non-anthropomorphic and a little more realistic than usual.
 * And the toys from that movie themselves, who only come to life if no one's around. The only time they ever break that rule is if someone actually treated that toy very badly.
 * Any work where animals will communicate in human language whenever left alone, but communicate in animal language when with humans.
 * The electrical appliances from The Brave Little Toaster (except Radio, who doesn't have a face), who can actually make their faces disappear whenever they've been spotted by humans.
 * The gargoyles from Disney's The Hunchback of Notre Dame actually only come to life whenever Quasimodo's around. If Esmeralda/Phoebus/Frollo/etc. is with Quasimodo, then the gargoyles will all still stay put.
 * And yes, like the Toy Story example above, they too have exceptions:
 * The lawn ornaments from Gnomeo and Juliet.
 * In Mannequin, Roxie (a mannequin which comes to life apparently because of a time travel experiment) can only be seen in her animated form by the man who built her. If someone else enters the room, peeks into the window, etc., she's instantly frozen until they go away.
 * Naked Fievel.

Live Action TV

 * The titular sifaka lemur of the PBS children's show Zoboomafoo is always anthropomorphosized at the very beginning of each episode by being fed a different snack. However, at the end of each episode, Zoboo actually loses his anthropomorphism due to the effects of said snack wearing off.

Newspaper Comics

 * Snoopy, from Peanuts would also go back and forth, not necessarily depending on his role, but more on his mood.
 * Garfield goes back and forth, but has noticeably become bipedal. The other cats can switch between the two stances as well.
 * Calvin and Hobbes has a variation on this. It was never confirmed whether Hobbes is really alive, or just a product of Calvin's imagination.

Videogames

 * Mother 3: Boney has to impersonate a kid to get into Club Titiboo, so Lucas dresses him up with a shirt and cap and he walks on hind legs for the remainder of the chapter (but quickly switching back to all-fours when they're in the wilderness again).
 * In the Super Mario Bros series of games, Koopas were originally depicted as quadrupedal turtles. As the series continued, they've been redesigned to walk on only two legs, and by the time of Paper Mario, they were completely anthropomorphized. However, in Super Mario Galaxy and Super Mario Galaxy 2, they've reverted back into being quadrupeds.
 * Before that, there were quadrupedal electrical enemy Koopas in Super Mario Sunshine.
 * However, Bowser and his son, Bowser Jr., both being Koopas, are completely immune to this even in these two games.
 * Also, Hammer Bros. and their ilk have always been bipedal, even in the original.

Webcomics

 * Justified in Freefall with Florence, who can run on all fours, but usually doesn't because it gets her hands dirty.
 * Mind you, this trope has nothing to do with the webcomic known as Sabrina Online, which is a furry webcomic with a main character named Zig Zag, 3/4ths skunk.

Western Animation

 * All of the Secret Garden residents from Father of the Pride walk on four feet while proforming on stage or around humans, then walk around on two when talking by themselves.
 * Tom, Jerry, and Spike from Tom and Jerry
 * Looney Tunes regular Sylvester is notable for being a normal, voiceless cat, a Civilized Animal, or a full-blown standard Funny Animal depending on the cartoon. He's also the only one of several more obscure Looney Tunes cats to do so.
 * There are many examples of Looney Tunes pet animal characters who are somewhat like this, including:
 * Tweety Bird
 * Hector the Bulldog
 * Charlie the Dog
 * When Wile E Coyote and The Road Runner has The Roadrunner as his adversary, he's mute and orders things from Acme Products. When he's paired opposite Bugs Bunny, he's an erudite Civilized Animal Gadgeteer Genius.
 * Another Looney Tunes example is Michigan J. Frog who goes back and forth between being an ordinary frog to a singing and dancing frog.
 * Taz experienced this somewhat in Taz Mania. Unlike in the original Looney Tunes cartoons, Taz is cast as a teenager who lives in a house with a family. He watches TV, collects bottlecaps, and even wears a suit and works as a bellboy at a hotel. Other times, he still partakes in his carnivorous behavior and acts like a wild animal as he hunts for prey, and is even hunted by some of the other characters like a wild animal.
 * Furrball from Tiny Toon Adventures is usually portrayed as an Nearly-Normal Animal cat, but he kept weaving back and forth between a normal cat and a Funny Animal depending on the cartoon. He would even switch between walking on two legs and walking on four legs.
 * Rita the Civilized Animal cat from Animaniacs with a lot of Talking Animal moments would switch between walking on two legs and walking on four legs. In a few cameos and possibly in part of "Kiki's Kitten", she is shown as a Funny Animal, and in a Cameo in "The Return of The Great Wakkorotti," she is even fully-dressed.
 * Chicken Boo is an Nearly-Normal Animal, but when he puts on a Paper-Thin Disguise, he becomes something of a Funny Animal.
 * The Goodfeathers are usually Talking Animals, but in "Star Warners" and a few other episodes, they are given more Funny Animal type roles.
 * Newt is a Civilized Animal, but he sometimes a Funny Animal and in "Puttin on The Blitz," he is a Nearly-Normal Animal.
 * Wilford B. Wolf is a geeky Funny Animal, but is a Petting Zoo Person when he becomes a handsome werewolf.
 * Felix the Cat. From 1919 through the mid-1950s, stories alternated between showing Felix as either a Talking Animal pet in a human home or a Funny Animal master of his own house. Only with the Trans-Lux TV series was Felix established as a Funny Animal for good.
 * Scooby Doo, although mostly a quadrupedal Speech-Impaired Animal, also had the ability to walk on two legs and act like a Funny Animal when the situation calls for it.
 * Family Guy has Brian Griffin, who started as a talking dog, but through the course of the series, he has become more and more human. Although every once in a while, you're reminded that he still is a dog.
 * A human example would be Stewie, who would go from being treated like a non talking baby by his family to being treated like any other adult by everyone else.
 * Courage the Cowardly Dog flips-flops between a Speech-Impaired Animal around his owners, Eustace and Muriel, to being a full-on Talking Animal around anyone else (human or otherwise) and to the audience.
 * Clarabelle Cow and Horace Horsecollar of the old Disney cartoon shorts and comics started out as actual four-legged non-anthropomorphic barnyard animals and alternated between anthro and non-anthro roles before becoming full-fledged Funny Animal characters alongside Mickey, Minnie, Goofy and the others.
 * Chip and Dale are Funny Animals in the Kingdom Hearts video game series, but are Civilized Animals otherwise.
 * Thundercats had the snarfs, who would switch between walking on two legs and walking on all four at times (and occasionally standing on their tails). The other Thundercats would do it too, occasionally.
 * Alvin and The Chipmunks: Alvin, Simon, and Theodore all started out as actual chipmunks, but in the first cartoon series they all started to look less like chipmunks, and in the second cartoon series they all looked even less like chipmunks. However, in their first live action movie, they all started to look like chipmunks again, although not as much as they did on the original covers.
 * Plato from Adventures From the Book of Virtues would often go back and forth between all fours and two legs.
 * Both Ravage and Ratbat from Transformers Generation 1.
 * Fat Cat in the pilot episode of Chip 'n Dale Rescue Rangers, back when he is still Aldrin Klordane's pet Right-Hand-Cat. After Klordane is arrested, he becomes anthropomorphic completely.
 * Eek the Cat is a Talking Animal/Funny Animal that often partakes in human activities, but is also a pet cat and cannot speak to his owners, although he appears to be able to speak to other human characters.
 * The animals in Barnyard and Back At the Barnyard walk on two legs, talk and partake in "human" activities, but when humans/a human show/shows up, the animals switch to a four-legged stance (except the birds, which are two-legged by default) and act like normal animals.
 * Invoked by Perry the Platypus on Phineas and Ferb. Around his owners he's a mindless domestic pet that "doesn't do much". In reality he's a super-capable secret agent that fights to save the world from evil. He still can't talk, though.
 * Teachers Pet
 * Background character Lyra Heartstrings in My Little Pony Friendship Is Magic is like this more than anypony else.
 * Everypony else in the Expanded Universe and The Merch.
 * Ponies in general have always been like this. It especially shows in My Little Pony Tales where one moment they could be running on four legs and another they can be standing up on two legs without an issue. Even G4 has this, with the ponies using their hooves as hands and moving around like humans when needed.