Cone of Shame

Tropey, stop biting that! You're going to pull out the stitches! I mean it! C'mere you!
...much better!

In veterinary practice, the Elizabethan Collar (known colloquially as a 'cone') has the purpose of promoting healing of a wound by preventing the animal from messing with it. It's effective enough. However, there is one big problem with this device...

It looks absolutely ridiculous.

It often appears as a large, white, plastic cone. Though a variety of alternatives to this design are on the market, this is the most recognizable. It makes the wearer look almost pathetic. Though the reason for it is usually medical, the result is a silly appearance and reduced line of sight. It is not abnormal to see a dog or cat with it on to run into walls or get stuck in a tight space. For this, it makes an appearance repeatedly in fiction. If it's a show with talking animals or funny animals, expect this to pop up at least once.

The Trope Namer is the movie Up, which uses the collar as more of a torture device than for medical purposes.

Examples of Cone of Shame include:

Film

Pixar's Up has Dug wearing it, and eventually Alpha. Here, it is for strict humiliation.
On Monsters, Inc., monsters who undergo decontamination by the CDA end up wearing one.
Grandsanta's reindeer in Arthur Christmas wears one.
Bosco the dog in One Crazy Summer, and at the end of the movie, all of Bosco's pups as well.

Live-Action TV

Stephen Colbert did this on The Colbert Report while recovering from a broken wrist. He attempts to pour drugs into his mouth. (How did he get the bottle open?)
Played for Laughs during a MythBusters build—after cutting down a large metal funnel, the leftover piece (which looked just like one of these cones) was plopped on Scottie's head.
One of the new interns in Scrubs tries putting one of these on a mentally ill patient to stop him biting the bandages on his hands. She is told to stop it.

Newspaper Comics

Get Fuzzy uses this a few times. Bonus Points for actually calling it the "cone of shame".
In Zits, Pierce wears one to try to cut down his mobile phone usage.
In Dilbert, Wally arrives at work wearing one, having injured himself pressing two buttons at once on his TV remote.

Tabletop Games

Impoding Kittens, the first expansion set for the Card Game Exploding Kittens, includes a Cone of Shame which is actually part of the game, and must be worn by a player who meets certain special conditions.

Web Comics

Cest La Vie: A human character, Michael, is forced to wear one as he cannot help picking at an operation site... Michael, we should add, is a little bit "strange" anyway; the author may be building him up into somebody asocial and undersocialized.
Two Lumps: Snooch had to wear a cone, and was using it as a megaphone.
In an early Kevin and Kell strip, this was the "tell" that made it obvious one of the students had had medical treatment.

Western Animation

The Family Guy episode Brian Sings and Swings has Brian wearing one after being hit by Peter's car.
In an episode of Martha Speaks, the main character has to wear one of these to prevent her from scratching her ear mites. She hates it, as it makes things 'sound funny', and scares away Baby Jake.
The Simpsons: When Mr. Burns' slant oil drill ruins Bart's treehouse (with him & Santa's Little Helper inside), SLH is reduced to wearing one of these while in a doggie-wheelchair.
Cleo got to wear one in the Clifford the Big Red Dog episode "Cleo Gets A Cone".
Tuff Puppy: Dudley has to wear one so he won't scratch at the horrible red rash on his butt.
In The Secret Files of the Spy Dogs it is revealed that the device was designed by dogs themselves - it is used by the communication teams for voice amplification.
Lucky from the Animated Series of One Hundred and One Dalmatians had to wear a cone after falling from a high tree branch and getting stitches. Cue humiliation from the other dogs.
Phineas and Ferb: Even platypuses aren't immune. Perry had to wear one for most of the morning, which was so big that it kept him from entering his lair, and subsequently, from thwarting Doofenschmirtz.
King of the Hill: Dale gets one of these after trying to put out head lice with chemicals from his extermination business (which went about as well as one would expect).
In an episode of The Powerpuff Girls, Bubbles is reduced to having to wear one of these after being stung in the throat by a bee.
In the Helluva Boss episode "Western Energy" Loona had to wear one after getting her "hellbies" vaccination (one of many indignities hellhounds like her have to endure in the twisted caste system of Hell) but at least the doctor gave her a lollipop.