Weasel Mascot

The recent^[when?] popularity of ferrets has created a new kind of animal sidekick character, in addition to the old standbys of the loyal, dull Dog and the smart, snarky Cat.

The weasel (or ferret) is a cute, mischievous, playful mascot who nonetheless looks out mainly for himself and can be very critical of people around him. He's nowhere near as clever as he thinks he is, and swears up and down he doesn't have to be fussed over. Until he wants to be, and frankly he's not about to turn down free food or attention if it's offered.

Animal mascot personalities normally fall into the Cat or Dog stereotypes even if the author has tried to use a more exotic animal, like a bird or mouse—it'll still act like a Cat or a Dog. The Weasel Mascot personality, likewise, may apply to non-mustelids (such as a mongoose or even a squirrel) -- but weasels, otters and ferrets are most common.

A major benefit of the Weasel personality is that it largely reflects the behavior of the real animal. This personality also applies to many positive cat depictions, especially in Japan where cats are hugely popular. The Weasel can make a good ironic deadpan snarker, without the nasty or untrustworthy streak westerners associate with the Cat. (Anyone who knows how weasels fare in older Western works should appreciate the deep irony of the previous sentence, but hey, times change.)

Many magical animal guardians are Weasel mascots, and most Weasel mascots are Talking Animals.

Definitely not to be confused with Weasel Words.

Examples of Weasel Mascot include:

Anime and Manga

Uzume the ferret in Ai Yori Aoshi.
Kero-chan in Cardcaptor Sakura
Yuuno, from Magical Girl Lyrical Nanoha is another actual ferret. He's an exception to the character type, though—he's a bookish, shy mage that gets nervous and blushes around Nanoha. This is mostly because Yuuno is not actually a ferret, but a human who poses as such.
Hippo the penguin in Mermaid Melody Pichi Pichi Pitch.
Japolo from Shamanic Princess.
Artemis's playful relationship with Minako in Sailor Moon's (versus Luna, who acts slightly more "parental" to Usagi).
Hisashi Sakisaka, an occasional recurring character in the Midori no Hibi manga, has a weasel sidekick, Tomahawk, on his shoulder at all times.
Although the series is realistic, and he is an actual ferret, the anime Ichigo Mashimaro has John, who belongs to the unbelievably-adorable Matsuri. John is cute, mischievous and playful, but that seems the extent of his Weasel Mascot traits.
Mepple in Futari wa Pretty Cure has an incredible attitude, and is greedy, picky, and likes to guilt Nagisa into doing things for him.
The manga Peach Fuzz, where the ferrets are the main characters... at least,they think they are. Their owners think they're just cute pets.
Used in Spirited Away, not that you'd be able to tell: the "Art of" book tells us that the character Lin is supposed to be a transformed weasel. She's sarcastic but sweet and quite cute.
Chamo from Mahou Sensei Negima! (with Dirty Old Man tendencies to boot!).
- He would like to remind you he's an ermine, thank you very much.
- There is a specific punishment for mages in Mahou Sensei Negima!: temporary transformation into an ermine. It is never stated directly, but some lines may imply that Chamo-kun did undergo such a penalty. Nevertheless, Chamo-kun always claims he is a regular ermine and mentions about his ermine family. He also revealed that he was banned from his home country for stealing panties from his girl ermine companions. This may be somewhat true. Just don't try to make a definite claim.
  - In the manga, he's pretty specific at several points in explaining he's an ermine sprite, which is where most of his powers—such as forming pactios and being able to read peoples' emotions—come from. He fled to Japan to find Negi to get him to hire him as a familiar so he wouldn't be punished for his panty theft.
  - What? But he stole them to build a warm nest for his sister...
Rafra from Infinite Ryvius.
Pokémon: Arguably, Ash's (previously Dawn's) Buizel is one of these despite the actual mascots being the Rodent of Unusual Size and the adorable yet overused Penguin. It initially followed in the tracks of previous Badasses Charizard and Sceptile, and did a very good job of it early on despite being a Ridiculously Cute Critter. Unfortunately, it hit a losing streak later on.
- In its first appearance, Buizel was the mascot of the traveling troupe in Pokémon Ranger and The Temple of The Sea and was the most prominent Pokémon until Manaphy appeared.
- Oshawott is the new mustelid on the team in Black and White.
Okojo San from the titular manga and the anime Siawase Apartment's Okojo-san is an ermine. He can't talk to people, but he can to the other animals in the apartment complex.
Bleach: While technically not a weasel, Kon sure has the personality for it.
In the new manga adaptation of Super Dimension Fortress Macross, Minmay has one of these, a bizarre rabbit/weasel hybrid that probably not exists in nature.
Naruto: During her Big Damn Heroes moment, Temari uses her fan to summon an eyepatch-wearing, scythe-wielding weasel named Kamatari that brings with it a massive swath of destruction against Tayuya.
- which to anyone who knows japanese is a pun on the word "Kamaitachi" which means "slicing wind" but "Kama" and "Itachi" means "sickle" and "weasel" respectively.
Popotan has Unagi, who also turns into an Anthropomorphic kemonomimi. Ironically, despite being the likely cause of the surge in ferrets-as-anime-characters, Unagi is actually a Hondo Stoat, a close relative to the ferret with rather distinct winter markings and a nebulous connection to faeries and magic in folklore.
Einstein the ferret in Alien from the Darkness, whose main hobbies appear to be searching for fish and molesting its female owner.
Candy from Candy Candy has a pet raccoon called Clean.
Kyubey from Puella Magi Madoka Magica. Given the nature of the show it's a subversion. There's a good reason that a good chunk of the show's fans don't trust him at all. Wicked Weasel, after all. He seems to be less of a subversion by the end of the show.

Comic Books

Weasel, the techie/hacker sidekick from the mainstream comic Deadpool. Not an actual weasel, but merely a man of shifty moral integrity who has his own weasel-head logo. Exists to get Deadpool both in and out of trouble.
Seamus the pooka from Blue Monday.
Spip, Spirou and Fantasio's snarky squirrel.

Fan Works

In reference to his Baleful Polymorph in Harry Potter and the Goblet of Fire, some fan fiction makes Draco Malfoy a ferret animagus.
Guardians of Pokémon has a pair of these, Jupei and Ki. This is not surprising as the author has stated that the fic was inspired by three anime: Pokémon (of course), Sailor Moon, and Cardcaptor Sakura.

Films -- Live Action

Kodo and Podo (aka "The Weasel Hankies") from The Beastmaster are a ferret duo that aid the main character Dar on his quests.
Along Came Polly features a pet ferret that often appeared in promotional material, despite having very few scenes in the movie.
Mr. Kimble has a pet ferret (pronounced "fyeuwr-it") that he uses to calm down his class in Kindergarten Cop. Said ferret even saves his hide by putting a well-timed bite on the Big Bad in the climactic showdown.

Literature

The weasels, ferrets, and stoats in The Wind in the Willows are loud and boisterous and take over Toad Hall, but they serve mostly as anti role models; in Terry Jones's (yes, that Terry Jones) film version they also serve as the Foil to Mole.
In Philip Pullman's His Dark Materials, Lyra's shapeshifting dæmon, Pantalaimon, often takes the shape of a weasel; he settles as a Pine Marten.
Harry Potter has Jarveys, smart-talking (very large) magical mustelids.
- Mr. Weasley's Patronus is a weasel.
  - His twin sons, Fred and George, have otters for their patroni, as does Hermione.
- Ladies and Germs, Draco Malfoy, the Amazing Bouncing Ferret!
The Areas of My Expertise: "Let's use my ferret to steal that diamond."
- "New ferret, same old con."
Ozzie from Avalon: Web of Magic is an elf who was magically transformed into a ferret. Besides being more goofy than snarky, he's pretty much this trope exactly.
The title character of Zucchini is a boy's pet ferret. The book was later adapted on CBS Storybreak.
In Spellbent, Jessie Shimmer's magical familiar is a Deadpan Snarker ferret named Palimpsest.

Live-Action TV

The announcer on Late Night Liars is a weasel.
In Ned's Declassified School Survival Guide an actual weasel supposedly infests Polk Middle School (whose official mascot is a wolf), and is the bane of the janitor's existence. It turns out to be pregnant and looking for a nest; it and its young are then adopted as second mascots by the moved janitor.
- The weasel ends up elected class president, over several more-qualified human candidates. (Actually, "more-qualified" is debatable...)
The Late Late Show with Craig Ferguson: "Do we have a picture of me with my ferrets?"

Music

"Weird Al" Yankovic's song "Albuquerque" features him being attacked by rabid weasels. Al gets his revenge in "Weasel Stomping Day".

Newspaper Comics

Played with in Get Fuzzy with Bucky's silent ferret nemesis, Fungo Squiggly.

Puppet Shows

Poink on The Funday Pawpet Show is sleazy, low down, and basically the show's comedic Chew Toy.

Video Games

Koppa from Shiren the Wanderer.
Daxter, after being turned into an ottsel, from the Jak and Daxter series. While he's not technically a weasel, he is a combination of two different kinds of mustelid: a weasel and an otter.
Torchlight launched with the choice of a dog or a cat as the character's animal partner, but a later official mod added a ferret as a third option.

Web Comics

Kiki from Sluggy Freelance... although her Genki Girl attitude may make her a subversion.
Wendy Weasel from Cwen's Quest plays straight (wo)man/big sister to titular character Cwen and keeps Cwen humble.
Menjou from Candi—who adds the "embellished" to the comic's Life Embellished nature due to being telepathic, telekinetic and at war with the local Squirrel Mafia. His "girlfriend", Snowflake the albino squirrel, is his Distaff Counterpart (swapping psi powers for Eye Beams).
Corasyn from Nothing Comes Naturally.
Annie from Demon of the Underground. She was found in Pogo's pants and took on a group of mooks while he was busy.
Girl Genius has "wasp eaters" - cute weasel-based constructs with eight legs and some implants, whom even their handlers usually call just "weasels". While not quite the comic's mascot, weasel plushie is a part of The Merch.

Western Animation

Rufus from Kim Possible, though actually a naked mole rat.
I Am Weasel!'s titular character is, unsurprisingly, a weasel.
Though really more of a "Winged Lemur", Momo from Avatar: The Last Airbender. Behaviorally, there's a lot of cat in him—specifically, Bryan Konietzko's cat.
- Pabu from the sequel series The Legend of Korra is a fire ferret—a combination of a ferret and a red panda. Yes, it's as adorable as it sounds.
Weasel Stomping Day from Robot Chicken and "Weird Al" Yankovic.
On the Darkwing Duck episode "Paint Misbehavin'", Freddie the Ferret is Launchpad's favorite comic book hero, famed for his "Friend Power."
Nils from the series Nils Holgersson has a hamster sidekick called Krumel who usually provides the voice of reason.
The Animals of Farthing Wood features the character Weasel, who is actually a rather sarcastic, selfish deadpan snarker.
An early episode of The Simpsons featured a Chuck E. Cheese expy called Wally Weasel's, complete with a literal weasel mascot and the slogan "we cram fun down your throat!"

Real Life

Literally a weasel mascot, the ferret from Blind Ferret Entertainment.
The website Play It Cyber Safe has a ferret for its mascot. It gets funny when they start saying piracy is theft when the word "ferret" means "little thief".
The Queensland Police in Australia are catching some flak due to their new anti-fraud mascot aimed at children: a ferret. Despite a) the previously mentioned meaning of the word, and b) ferrets are illegal to own in the state of Queensland
Dancing Ferret Discs, an alternative music label, has a stylized ferret as part of its logo.
Ferrets do indeed tend to have very hyperactive and playful personalities in real life, with a special emphasis on hyperactive; something to keep in mind for households with small children. They also like to chew on things, so by all means don't leave your leather goods within their reach.