Abuse

Simply put, this is the classification given to most Fluffy Pony content of a negative or graphic/gory nature. As fluffy ponies are "This is so fragile which is broken by all", this is the predominant form of fluffy pony work.

Background
Fluffy Ponies were originally conceived of as being like the ponies in My Little Pony: Friendship is Magic, living in the magical lands of Equestria. They would be a mentally-challenged ableism-based sub-race, characterized by their coats being enormous and fluffy. Fiction involving them was relegated to either stories of them dying in amusing ways, usually by accident, or humans/normal ponies observing their odd characteristics.

After the popularity of the MLP fanfiction "My Little Dashie" more stories came up which further explored the idea of humans interacting with fluffy ponies until the majority of the fluffy fandom stopped making stories set in Equestria. The tone of these stories quickly shifted towards a setting where fluffy ponies became man-made pets living on a contemporary, slightly dystopian Earth. Due to the hatred of the "My Little Dashie" story's popularity at the time, one of the most abused mlp style fluffies was Rainbow Dash, to take jabs at the stories fans. The term 'abuse' originated from the concept of stories involving owners harming their pets. It has now expanded to be a broad term for harm brought to fluffies.

Current Usage
Fluffy pony abuse is a label that is generally applied to any kind of picture or story where one or more fluffy ponies suffer in some way. It can range from harmless jokes being played upon the easily confused fluffy ponies and owners disciplining their pets, to elaborate torture sessions where hapless fluffies are mutilated and slowly killed. Example: Fluffies being forced to commit terrible acts like raping foals and cannibalism, and entire herds being violently massacred by humans or other animals.Occasionally, the label is used in conjunction with Sadbox, Hugbox or Questionable tags to show that bad things happen to the fluffy pony.

In abuse stories, the point of view may change between the abuser and the fluffy pony victims. While in the abuser's point of view, the reader is given an explanation why and how the fluffy ponies are to be abused, the function of drugs, utensils or apparatuses involved in the fluffies' misery, and the state of satisfaction of the psychopathic human at the end of the story. Taking the POV of a fluffy allows readers to see how fluffies perceive and experience their misfortune, the emotional response towards the abuse, and how they try to rationalize the situation in their minds.

Depiction of fluffy ponies in abuse-aligned stories
Other than their appearance and behavior, other elements help add to the success and popularity of the fluffy pony franchise. Descended from the highly fertile laboratory prototypes, fluffies are so easy and cheap to mass breed that it causes product inflation. They can be bought for cheap prices from ordinary pet stores, as well as private and usually shady breeders. The sales for fluffy ponies have been received with mixed opinions by society. The sudden spike of interest for these new creatures has caused sales for other kinds of pets to decrease, leading to a controversy among those who believe fluffies should never have been created, referring to them as nothing more than industrialized, mass produced biotoys that shouldn't compete with 'real' pets. Even PETA, the organization that is blamed for releasing fluffy ponies in the first place (see headcanon origin) has officially stated they oppose the existence of fluffies, but they don't approve of fluffies being tortured or abused. They believe all sales and breeding should come to a complete stop, and all fluffies be euthanized in a humane manner. Their opinion is disregarded by abusers.

Fluffy ponies have seemingly contributed to an unusual change in human society and for other pets. Criminal reports regarding animal cruelty has been lowered by a fair bit. It's been speculated that the cause behind this is that perpetrators of animal cruelty have grown more interested in targeting fluffy ponies for their cute appearances, innocent attitudes and their ability to vocalize fear and pain. In addition, fluffy ponies are officially classed as "biotoys" and not animals, thus they are not protected by any animal rights or laws. As such, any human may freely kill feral fluffies (which are classed as vermin) without suffering any legal consequences, provided that any carcasses are disposed of afterwards. Failure to clean up may result in a fine for causing litter and insanitation. The killing of ferals is in fact encouraged in rural and urban areas where fluffies may be more densely populated. It is generally looked down upon to kill feral fluffies in public, as the violence and cries of pain and fear may upset or traumatize adults and children who are fond of the creatures. Killing someone's domestic fluffy, on the other hand, is illegal and counts as property damage. Medical, military, and biotechnology corporations dealing with research and development can use fluffy ponies for their experiments, because they are seen as tools rather than animals.

Not only are fluffies bred to become pets, accessories or torture victims, they are also frequently sold as a low-priced food source for other pets. Some owners of pet snakes and spiders also have a pair of fluffies and let them breed freely to create new fluffies to feed to the other pets. Even if the breeding fluffies will eventually realize their offspring are only raised to become food, they are usually too stupid to stop. Adult fluffies are too big for spiders, but foals are a more appropriate size for tarantulas. Zoo keepers sometimes feed living fluffies to tigers, lions, crocodiles and other meat eaters that prefer live prey instead of slabs of meat. Humans can also eat fluffies, and their flesh is considered sweet and tasty if prepared correctly. However, because they are generally associated with filth and diseases, this is not too common, and because of their small size, fluffy ponies are not very filling for humans, making fluffy ponies more of a morsel than the main course. Hikers and hunters in the wild, as well as homeless people, however, are said to to occasionally eat captured feral fluffies for a sizable snack, provided they have a means to cook them.

Fluffies Abusing Fluffies
Fluffy pony abuse is not restricted to humans abusing fluffies. Fluffies are also known to abuse their own kind for various reasons. Feral herds are prone to abusing other fluffies as well as their own members. This can range from a Smarty's friends giving some ponies less in favor of others, to outright war, rape and pillaging. Maroon, as depicted here, is a prime example of a fluffy that abuses fluffies.

Fluffy brats are also known for instigating abuse. Booru user KMEB's "Goldie" is a well-known pony exhibiting this behavior.

Due to the finicky use of the term 'abuse', ordinary domestic acts such as fighting for toys/food can be seen as abuse between fluffies.

Occasionally, normal fluffies will abuse each other due to their own stupidity. The domesticated Montgomery became infamous for this in his debut appearance, killing two foals, raping a mare and using the same mare as a landing pad at the expense of her life. As this was done without ill will, it may be seen as questionable.

Often times, those who love fluffies will grow to hate a fluffy that abuses other fluffies, and may beg or demand that the author or artist kill or abuse that abusive fluffy. As such, a common tactic for trolling fluffy lovers (And usually used in ragebox) is giving the abusive fluffy a happy ending.

Accidental Abuse
Fluffy ponies are notorious for being incredibly fragile, and it doesn't take much to hurt or kill them. Some works focus on this aspect of fluffies. In accidental abuse stories, carelessness, stupidity (both on the part of humans and fluffies), bad information, or just sheer bad luck is the cause of the fluffy suffering, rather than any malicious intent. It is used often in conjunction with the sadbox tag, but can also be played for laughs. Accidental abuse is also used as a plot device in hugbox stories, where owners accidentally hurt their fluffies and must try to repair the relationship. A variation on this is where a seemingly loving owner accidentally hurts their fluffy, discovers the sick pleasure that hurting fluffies brings to that specific person, and then begins to intentionally abusing their fluffy.