Changelings are a parasitic pony species, meaning they need to use other sentient creatures in order to survive.

The most prominent proof of this is how they only feed on other creatures emotions. That is all they eat, and what they need in order to not starve to death. The process off feeding on emotions is a purely magical process, either remotely (example) or through the more direct aproach by penetrating the victims with their giant fangs and draining them. Draining their victims in this way usually ends in the victims death however and is to be avoided.
Once the process is complete the victim is left emotionless and unresponsive like some sort of husk. When in this state many of the changelings victims are taken back to the hive where they are cocooned and left to recover, so to later be fed on once again.

Female ponies (and the occasional griffon the changelings might aquire) however sometimes gets brought to the egg chambers where they are to be used as incubators, or broodmothers if you will, for the next generations of these bug ponies. Changelings themselves do not have any reproductive organs and so they need to use their magic in combination with other creatures biological structures in order to reproduce.
Depending on what species the broodmother is the offspring takes on slightly different apearences and talents. The most commonly known types are pictured above.

Only alicorn broodmothers are able to produce hive queens yet there can only be one queen for each hive. This means that when the queens hatch and reach maturity they will fight eachother for leadership of the hive. The winner gets the hive and the losers either dies or flees to start their own hives.

Unicorn broodmothers create unicorn changelings. These changelings have stronger magical abilities than their brethren and are the only ones, along with the queen, who are able to “fertilies” the “incubators”. They have a closer relationship with the queen and she will usually hand pick a few to act as her personal body guards and advisors. The ones who aren’t chosen for these tasks work in the egg chambers and nurseries caring for the future of the hive. (a unicorn patrolling the egg chambers pictured above)

Pegasus broodmothers create pegasus changelings. Pegasus changelings are the ones who are most oftenly seen outside of the hive, making many ponies across Equestria to believe that that’s how all changelings look. They all work as warriors and hunters, bringing food back to the hive and excecuting attacks on towns and villages under the queen’s comand.

Earth pony broodmothers create earth pony changelings. These are the type of changelings that are the most common yet rarely seen outside of the hive. They are the everyday workers and builders, caring for the food brought in by the hunters and expanding the hive. Their lack of wings make them not as effective as the hunters for launched attacks yet they are the first line of defence if the hive is to be attacked directly.

Griffon broodmothers create hippogriff changelings. Griffons are a very rare creatures to find in the hive. This is because of multiple reasons. Firstly they are rare and hard to find, secondly griffons are very aggressive and is hard to capture and thirdly they do not carry as much love and affection as ponies usually do making them a meager meal. However when the hive does manage to capture a female they are almost instantly put in the egg chambers. Hippogriff changelings are incredibly strong and durable making them excellent warriors and hunters, joining the top ranks of the pegasus changelings.

There have been some rare times were different creatures have been used as incubators such as: donkeys, yaks (making super strong yet highly unstable changelings), zebras and in the most recent case of strange broodmothers, draconequus.

Broodmothers are used constantly until they are expired, whereupon they will be uncerimonly dumped in the surrounding forests and a new fresh incubator taking their place. Each incubator lays between 3-9 eggs with each clutch of eggs. The eggs take about 11 months to develope, much like a normal pony pregnancy.

Changelings themselves have a very long lifespan and little is known how old they can actually get. Most of them die from other things such as extreme weather, starvation and fighting. The current hive queen, Chrysalis, is said to be over 400 years old. Her incubator was none other than one of Celestia’s children making her very strong and powerfull. (so technically Chryssi could be considered Celestia’s grandchild, if you’re feeling morbid enough)

As stated, changelings live in hives. These hives normally hover in the air, much like cities such as Cloudsdale and Los Pegasus. Changelings often choose to build their hives inside of mountain passes and or in the cover of thick fog or clouds, far away from pony civilisation.
Typically the hive is made up of one large main hive with smaller sections floating around it, housing some of the lower ranked flying changelings. The hive is built in layers with growth like extensions always added on untill a new layer, or “ring” can be added.
The few ponies who have been inside the hive and miraculously come back to tell the tale says that the insides are built as a huge, completely indoors, city. With shops, bars, “houses” and more. Making them not at all as primitive as they seem to be, other than in their extreme temprament and instinctual actions.
The queen is said to live in the biggest construct in the very middle of the hive.
The only part that could be considered crude and uncivilised is the egg chambers and caccoon caves where they keep their reserve ponies.

One last bit of information about changelings is that they all share a special mental bond with eachother and especially their queen. Sensing eachothers pressence and having the ability to relay vauge orders when orchestrating an attack.

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Ok… that was a lot of shitty text with a sea of spelling erorrs and gramatical problems. But since im lazy I will leave it for now. I hope I didn’t forget anything…

Oh well!

This is, if you hadn’t noticed, my headcannon for changelings. I felt like I needed to explain how I see them a bit as they are going to be kind of a big part of my next gen verse. And oh god I just LOVE all this morbid stuff xD

I got inspired by the game series “Dragon Age” (BEST GAMES 10/10 WOULD KREM AGAIN) with the whole broodmother thing (example of a broodmother in the games, be warned its nasty! That used to be a dwarf D: ), depending on what race she is she will produce different kinds of monsters kind of. Only I didn’t play that much into the whole body horror part. Although I must say I was a bit tempted to at first xD

In my verse changelings are basically the spawn of satan or something xD just overall terrible and basically irredeemable. Making Thorax all the more interesting as a character since he just wants to break away from what he is.

The Discord triplets are a slight exception to some of these things such as being able to eat other foods and having some of their dear old mom/dads chaos magic.