Changeling
The Changelings were shapeshifting lifeforms  (in their natural state a liquid) native to the Gamma Quadrant of the Milky Way Galaxy. They were the creators and rulers of the Dominion, whose subject races knew them as the semi-mythical Founders. Most Changelings existed as an amalgamated mass known as the Great Link.

Biology 
The natural form of a Changeling was a viscous orange liquid containing a structure known as a morphogenic matrix. () They contained morphogenic enzymes responsible for their shapeshifting ability. ()

Changelings (or at least young and inexperienced ones, like Odo) had to revert to their natural liquid state to regenerate every sixteen to eighteen hours. Preventing them from doing so would cause severe physical distress and their forms to begin to deteriorate and "flake" away. ()

Changelings could take virtually any corporeal form. () They, or at least the Founders, also had the ability to closely mimic humanoid personalities to the point where even close friends and family often could not distinguish them from the originals. () They could transform parts of themselves into smaller electrical devices, like a combadge, and make it operational, and were also capable of at least mimicking the shape and operation of a computer. () Changelings could also mimic the form of fire and clouds. ()

Starfleet sensors, as of 2371, failed to recognize Changelings when they mimicked other forms. ()

The Obsidian Order created a prototype quantum stasis field generator that could prevent a Changeling from shape shifting. ()

Changelings could survive in the vacuum of space, and were highly resistant to disruptor fire. ()

Changelings – or at least Odo – had no sense of smell. () Laas stated, however, that if his hands had Klingon blood on them, they would emit a stench, possibly suggesting that after living among solids for years, he was at least familiar with the concept. ()

Even when in humanoid form, Changelings did not need to take in sustenance. Odo noted that he once attempted to eat after assuming humanoid form for the first time, but found the experience not only unsatisfying due to his lack of taste buds, but "messy" for reasons he chose not to elaborate. () Doctor Bashir once asked Odo for a sample of himself to study its value in possibly creating synthetic organs, which raised the question how he would get that part of himself back, if he never added matter to his body. ()

The thoughts and emotions of Changelings could not be read by Betazoids. () But, memories could be telepathically transferred by a Guardian to one in the Trill Zhian'tara ritual, and they could participate as a past Trill host. () A telepathic energy matrix (which caused the crew of Deep Space 9 to fight for control of that space station) was rejected by Odo's lack of a humanoid brain. It did have the ability to warp his face and knock him unconscious, though he retained his humanoid shape. () 

However, on one occasion Odo was knocked out by being struck on the head. ()

There was an apparent telepathic aspect to the Changeling species, evidenced in the fact Odo felt drawn toward the Omarion Nebula, which was once home to the Founders. () However, it is possible that the instinctive desire to visit the nebula was "hardwired" into him. Changelings had the ability to sense, in most cases, the presence of other Changelings. () The Jem'Hadar may also have the ability to sense Changelings, though this ability might not be telepathic but an imprinted response to a Changeling's gelatinous state, as a child Jem'Hadar who sensed Odo did not respond to him until he temporarily reverted to that state. () Further suggestion of a telepathic trait arose when Odo's remaining morphogenic enzymes were stimulated by a plasma field, creating a miniaturized "Great Link" with Benjamin Sisko, Jadzia Dax, and Elim Garak. ()

At the very least, there exists a "hive mind" among the species when joined with the Great Link. () For instance, Odo once commented, "During the Link, I sensed that the other Changelings were trying to hide things from me... faces, names." ()

The Founders of the Dominion were Changelings, and made up the majority of the Dominion's leadership. Changelings preferred to think of themselves as a drop (the individual) in the larger ocean (what they called the Great Link). A Changeling, therefore, typically had little sense of individual identity. Being a liquid-based lifeform, in order to link with other Changelings, they simply reverted to this state and the liquid blended together, creating a link between them. () Centuries before, the Founders had sent the Hundred Changelings throughout the galaxy as a way to gauge other species by the way they treated the weak and vulnerable. () There were legends of Changelings having been on the planet Rakhar. ()

It was suggested that Changelings were biologically immortal and therefore never died of old age () Laas was over 200 years old. () However, it was possible to kill Changelings by a number of means. Severe cases of radiation poisoning could prove fatal. () Changelings were also killed by phaser or disruptor fire, at sufficiently high settings. () A Changeling was observed succumbing to trauma following the impact of a ship crashing into a planetary surface (a crash in which the ship's inertial dampers had failed). () The Admiral Leyton/Miles O'Brien Changeling laughingly remarked to Sisko that, including himself, there were only four Changeling agents in the Alpha Quadrant. () Of the four three were dead:
 Krajensky (Changeling) in 2371 ()
 General Martok (Changeling) was killed by the Klingons in 2373 ()
 Dr. Julian Bashir (Changeling) was killed in the destruction of the USS Yukon in 2373 ()

Changelings could assume the forms of both male and female humanoids. () The majority of Changelings appeared to favor either a male or female form, even when impersonating individual solids. () It was unknown if this indicated a true biological gender or gender identity, or was simply a matter of personal preference. Changelings could experience feelings of physical attraction and love towards solids, and were capable of sexual intercourse with them, and with each other while in humanoid form. However, a Changeling could not have children with a solid. () 

Changelings began their lives in an "infant" state, as a small quantity of seemingly inanimate liquid. In this state they were capable of limited shapeshifting, usually into simple geometric shapes, and responding to external stimuli such as moving away from an electrical charge. Over time they developed into maturity, increasing in mass and gaining greater understanding of their surroundings and control over their shapeshifting abilities, eventually becoming capable of verbal communication and assuming complex forms. () Dr. Bashir once jokingly suggested that Changelings may experience an equivalent to puberty or menopause (). 

Despite the existence of infants, it was unknown how Changelings reproduced. Garak expressed doubt over whether or not Changelings have mothers. () Changelings regarded all other members of their species as their "family", although it is unclear if this indicated a genetic relationship, or merely a social one. ()

A Changeling could also be transformed by the Great Link into a solid permanently. () Also, an infant Changeling once transformed Odo into a Changeling again by absorbing itself into his body, but it had also been dying at the time, so it is unknown how this would have normally affected the 'giver'. ()

Culture
Changeling culture revolved around the Great Link and shapeshifting. While in the Link, a Changeling had little sense of time or its individual self, and saw itself as a part in a larger whole. Changelings hated to be separated from their people, and would seek out the company of other Changelings with whom they had personal conflicts rather than remain alone. () Changelings considered linking with one another the ultimate form of intimacy, and many found spoken language and other expressions of intimacy such as sex limited. () Being in the Link was described as "paradise" for a Changeling, and even Odo, who bitterly opposed the goals of the Founders dreamed of returning to it. ()

Most Changelings, including Odo, displayed a marked preference for order, efficiency, and following rules, which Odo interpreted through the lens of justice but other Changelings viewed through the lens of control. () Odo once commented to Worf that "My people have an innate need for order", suggesting the compulsion may be biological in origin. ()

Throughout their entire history, no Changeling had ever harmed another. () Above all else, the Changelings wanted their people to all be united in the Great Link, and renegades such as Odo were given ample opportunities to return home with all transgressions forgiven. Weyoun 4 informed Odo that the Founders wanted him back after he first rejected them. () The  allowed Odo to leave the Battle of the Omarion Nebula unharmed, and the  attempted to convince him to escape the self-destructing Defiant with it. () The Female Changeling prioritized returning Odo, who was previously banished, back to the Link over the outcome of the Dominion War. ()

Shapeshifting gave Changelings physical empathy with other lifeforms, allowing them to gain knowledge of them, though they spent most of their existence in the Great Link. ()

History

Legacy 
In 2380, when Beckett Mariner was suspicious about Brad Boimler's relationship with Barbara Brinson, she included Changelings in her list of what Barbara might be. ()

In contrast, in the same year conspiracy theorist Steve Levy claimed that Changelings were not real, and that "the Dominion War didn't happen." ()

Mirror universe 
In the mirror universe, the Bajoran wormhole remained undiscovered as of 2375. Therefore, Changelings and other species native to the Gamma Quadrant remained unknown to the peoples of the Alpha Quadrant. The only exception was , who was killed on  during a workers' revolt in 2370. ()

People 
 Female Changeling
 Laas
 Odo
 
 
 
 
 
 List of unnamed changelings

Appendices

Appearances 
A list of all appearances of Changelings (excluding the regular appearance of Odo):
 
  (Season 1)
  (Season 3)
 
 
 
 
 
  (Season 4)
 
 
  (Season 5) 
 
 
 
 
 
  (Season 6)
 
  
  (Season 7)
 
 
 
 
 
 
 
 
  
  (Season 4)

Background information

Examining the species 
The writers of DS9 believed there was a common "rigidity" among both the Founders and Odo. Robert Hewitt Wolfe described this characteristic as basically being "an obsessive-compulsive control freak." ()

 suggests Changelings have a lifespan of at least two hundred years, although if Odo was indeed two hundred years old when he traveled back with the  in an alternate timeline in , that would indicate Changelings could live for at least four hundred years. It has also been suggested that Changelings might be immortal, with the Female Changeling remarking (in ), "You are a Changeling, you are timeless" – a logical assumption, given that the cellular structure of Changelings appears to be so fundamentally unique that it is incapable of decay.

Though Odo and Laas have been described as male and the Female Changeling as female, it is unclear what anatomical differences, if any, exist between male and female Changelings. Odo was able to assume the form of the Female Changeling, in . 

Also, although an infant Changeling appears in , it is never made clear exactly how Changelings reproduce. Odo did display romantic affection for some female humanoids, most notably Kira Nerys, and was capable of sexual intercourse with humanoid species. He even had a sexual encounter with the Female Changeling, suggesting that two Changelings can mate in humanoid form, though the Female Changeling considered this version of intimacy unnecessary for their race, and pale compared to the Great Link. () Ronald D. Moore opined that Odo could not reproduce with solids as he did not have the "authentic...
gear" to fertilize an egg. 

The Changelings frequently assumed a form similar to that of Odo; however, Odo's unique appearance was the product of his difficulty with assuming convincing humanoid forms, not mandated by his racial makeup. Other Changelings have no difficulty with assuming convincing humanoid forms. The first time this was established was in . "Not only do they look like you, but they copy your brain and know what you know. That's very dangerous," said René Echevarria. (Captains' Logs Supplemental - The Unauthorized Guide to the New Trek Voyages, p. 91) As the Changelings other than Odo are capable of looking identical to humanoids, they must therefore assume an Odo-like form out of choice. This may be because, before meeting Odo and the races of the Alpha Quadrant, they had no need to reveal themselves individually to outsiders, and thus had no need for a unique humanoid form to differentiate themselves from other species. Odo would have provided them with a useful template. Ronald D. Moore commented, "Odo modeled his look after Dr. Mora and the Founders then modeled their look after Odo. They did this initially as a compliment and way of reaching out to their long-lost Changeling, and later they kept doing it as a dig and reminder to him of his own limitations."  Although much older than Odo, Laas also seemed to have similar facial features, probably because of the same reason. Having been found by the Varalans, it can be assumed that the unique bumps on his forehead are typical Valaran features. (However, Odo doesn't have the Bajoran facial features of Mora Pol and other Bajorans; he comments in  that he always had trouble with their noses.)

The Female Changeling appears to be left-handed in . However, Odo seems to be right-handed during the course of the series. It is unclear whether a Changeling has a dominant hand when assuming humanoid form, or simply chooses which hand to use for different tasks.

Odo assumes the shape of a computer in , but it is unknown whether he could simply mimic the computer's form or whether he could actually perform the complex calculations a computer makes.

Changelings do grow physically, to a point; as Changelings don't eat or drink, it is unclear exactly where the 'new' mass and energy come from. In , Julian Bashir asks Odo for a sample of his liquid form, and Odo only agrees on the condition that he will get it back after Bashir's tests are complete.

The articulated goo of the Changelings was probably one of the most challenging special effects to create for . The standard process of creating the effect and inserting it into scenes typically involved action plates, background plates, blue-screen photography, and CGI, all integrated together, as seamlessly as possible. The Changeling goo (also known as "Odo goo") was specially designed computer animation. There was also a generic wire-frame CGI model that could be animated for representing the beginning of a Changeling transforming from its liquid state into its humanoid form. (Cinefantastique, Vol. 27, No. 4/5, p. 104)

Episodic developments 
Apart from Odo, Changelings were first mentioned in . In , it is suggested that a malevolent Changeling (who turns out to be Odo) is responsible for several attacks on space station Deep Space 9, although Ira Steven Behr was unimpressed with this plot point. "The red herring didn't quite work for me all that much," Behr commented, "but it's window dressing [....] It doesn't annoy you because you're buying the package." (Captains' Logs Supplemental - The Unauthorized Guide to the New Trek Voyages, p. 68) Changelings other than Odo were referred to again in , which Robert Hewitt Wolfe noted was one of the first mentions of the Changelings having a mythology and being mythological lifeforms. "[It] was a really nice bit. It's just one of those things; it's like that little seed that you start rolling down the hill, and it just gets bigger and bigger." ("Section 31: Hidden File 02", DS9 Season 2 DVD special features)

The Changelings were thereafter introduced in . In that episode and , Michael Westmore was required to create the makeup for the Founders as well as Odo. For the non-speaking Founders, Westmore simply used foam latex appliances from the exact same molds as were used for Odo. The makeup designer specifically requested casting, for these parts, actors whose faces were similar in size to Odo actor Rene Auberjonois. For each of the Founders with dialogue, a mold was taken of their face then an Odo-like mask was sculpted over it. Explained Westmore, "It's all one solid piece that glues down around the mouth and eyes. The problem with that face is it has to line up perfectly with the mouth and eyes." (Cinefantastique, Vol. 27, No. 4/5, p. 113) Another issue with the Changeling makeup during the making of the "The Search" two-parter was that each mask could be accidentally broken by its wearer laughing. (, issue #222, p. 30) Although the makeup department attempted to use the Odo mask for other Changelings as they started appearing, some of the faces of the performers portraying main Changeling characters were so unique and different that Auberjonois' mask couldn't be a one-size-fits-all prosthetic appliance. Consequently, the makeup department ultimately had to craft new masks for principal Changelings. A typical example of such makeup (Odo's) usually took two hours to apply. (Star Trek: Aliens & Artifacts, pp. 137 & 139)

The sophistication of the average morphing shot was increased tenfold for . Visual Effects Supervisor Glenn Neufeld was hugely surprised by the complexity of that footage, which the visual effects team had only six weeks to do. (Cinefantastique, Vol. 27, No. 4/5, p. 105) Morphs performed by Changelings in "The Adversary" were actually designed by Glenn Neufeld and executed with CGI by VisionArt Design & Animation. (Cinefantastique, Vol. 27, No. 4/5, p. 114) "We had a ton of morphs," said David Livingston. "You're never going to see more morphs in forty-three minutes than you will on this show." The extreme amount of morphs in "The Adversary" resulted in the episode having an unusually long production period. (Captains' Logs Supplemental - The Unauthorized Guide to the New Trek Voyages, p. 99) Michael Eddington actor Kenneth Marshall witnessed, first hand, the shooting of some of the footage required for the morphs. "It's fascinating how they do the morph sequences," he commented. "I haven't actually seen them do the special FX, but they shoot it three different ways on the set. In the last shot, everyone tiptoes off the set so as not to disturb anything even a fraction of an inch." ()

Due to the Founders infiltrating the Alpha Quadrant, there was much conjecture about which of the characters might be a Changeling. "Many people have gone down many different paths with [speculating] who is a changeling and who isn't," observed Ira Steven Behr. "There's some great theories." ()

More Changeling sequences were created in CGI for "The Begotten", involving Odo and the Changeling infant in separate shots. For one scene in which Odo watches the baby Changeling shape-shift into a rough approximation of his face, the two Changeling characters were filmed on either side of a split-screen shot. Also, both footage of Odo transforming into a hawk in "The Begotten" as well as a shot showing the demise of a slowly dying Founder in  were created with CGI done by VisionArt. (Cinefantastique, Vol. 29, Nos. 6/7, pp. 41 & 42)

Several shots of Changelings were also created with visual effects for . In that case, the footage included Laas in the form of a fish-like creature, flying through space, and Odo representing shimmering lights. Both shape-shifting sequences were worked on by Visual Effects Supervisor David Stipes, Visual Effects Coordinator Adam Buckner, and CGI effects company Digital Muse, where Matt Merkovich participated in rendering the footage as CGI with the computer program LightWave 3D. Stipes was impressed by both of the two sequences. (Cinefantastique, Vol. 32, Nos. 4/5, pp. 64, 65 & 66)

Robert Hewitt Wolfe remarked that the figurative seed he imagined being rolled down a hill with the advent of Changeling mythology in "Shadowplay" was, by the conclusion of the series, "just huge." ("Section 31: Hidden File 02", DS9 Season 2 DVD special features)

Morphs done by Changelings in DS9 series finalé  were created by Digital Muse and were intended to be as similar as possible to the other morphs in the series. "David Lombardi is doing some of them, and Brad Hayes," noted David Stipes. (Cinefantastique, Vol. 32, Nos. 4/5, p. 90)

Apocrypha 
In the Worlds of Star Trek: Deep Space Nine novella Olympus Descending, Odo learns from an elder Changeling that there are no "infant" Changelings, but just Changelings that are kept separate from the rest of the Great Link, as Changelings cannot reproduce since the departure of the ancient Progenitor centuries ago; Odo, Laas and the rest of the Hundred were sent out to find the Progenitor. During the novel, Odo discovers what appears to be the corpse of the Progenitor, prompting the rest of the Link to disperse, leaving Odo and Laas as the only two Changelings left to manage the Dominion.

External links 
 
 

de:Wechselbalg
ja:可変種
nl:Vormverwisselaar
ru:Меняющиеся
Nicknames
Species
Telepathic species