Changelings cannot alter themselves enough to change physical sizes (i.e, changing from Medium to Small, etc). It is worth noting that while a changeling could technically shift into something like an aarakocra, their wings would be non-functional.
A changeling can't make the wings at all. If they had wings, like from a class feature or something, then they could look like an Aaracokra with wings because they will have those limbs at that point.
A changeling can make it LOOK like they have sharper teeth or claws, but this doesn't actually give them natural weapons; it's a deception. Essentially, it is a form of disguise self, NOT alter self.
Most changelings don't know they're changelings.
Though they may always feel somewhat different or removed from human life, most changelings are too young to understand who they truly are.
If you want it to be able to grow a tail when it changes into a tiefling or tabaxi, it is your choice. It is also your choice if you want the tail to be prehensile and able to grab and hold stuff. You can appear as a member of another humanoid race which will include things like tails, frills, gills, wings, horns, etc.
Appearance. In their true form, or their form "at rest", changelings have pale skin, colorless eyes that can be completely white or completely black, and white or silver-white hair.
Changeling blood is green, unlike most other animals. Changelings, despite their thinly and seemingly fragile frame, are capable of surviving otherwise fatal injuries thanks to their magical abilities.
Most often it was thought that fairies exchanged the children. In rare cases, the very elderly of the fairy people would be exchanged in the place of a human baby, so that the old fairy could live in comfort, being coddled by its human parents.
Changelings born from two changeling parents are born in their natural form: pale, slender, with colorless eyes and white hair.
The short version is that a Changeling can shapeshift to a form that can produce sperm to impregnate someone, and can shapeshift to a form with a uterus and eggs to get pregnant, but a pregnant Changeling cannot shapechange to a form without a uterus without ending the pregnancy.
The Gift of Water is the blessing of the Waterborn. The changelings blessed with it can spend one point of Glamour to allow the changeling to breathe underwater and swim at a terrific rate (equal to twice the character's Speed rating) for the rest of the scene.
A changeling can eliminate or add traditional physical disfigurements - such as scars or birthmarks - when changing shape.
Changelings typically have large eyes with narrow pupils, ranging in color from white, to yellow, to black. Hair colors are similar: Light grey, platinum blonde, shades of silver, all the way to the darkest hair color being a light brown.
If the changeling has lost a limb, the limb is missing in every form they take. If they haven't lost a limb, every form they take has all the limbs the changeling normally has.
They have large colorless eyes circled by thick black rings. Their hair color is most commonly a light shade of silver followed by platinum and blonde. In rarer cases, their hair can be pale shades of green, pink, and blue. Similar to elves, changelings lack body and facial hair.
According to Big Jim, some changelings have completely lost the ability to fly with their transformation into the new race.
Unlike doppelgangers, which are entirely genderless, a changeling does have a default gender that manifests in adolescence, but each changeling can adapt his or her form to be of either gender, hermaphroditic (both genders simultaneously), or entirely genderless.
Conversation. By RAW changelings revert when they DIE but not when they are unconscious (it would be hard to maintain a long term masquerade if you revert when you sleep!). I bet suggested that a piece of a Changeling — such as cut hair — WILL revert, but that this is slow and may take up to 24 hours.
Changelings don't inherently recognize each other. If they don't want to be recognized then when they do something suspicious it would be an insight check against the changelings deception, which the changeling has advantage on. A changeling could have expertise in insight from divergent persona.
If you're Irish, you know your child is a changeling if it's sickly and doesn't grow in size like a normal child. Another fairly obvious sign is if it grows a beard or has long teeth. Finally, your child might be far more intelligent than other kids that age, and possess unusual insight.
Babies are most at risk, although the Sidhe fear nothing more than iron and fire, so a pair of scissors or tongs may be left near to the crib, or the crib left close to a fireplace, and draping a garment belonging to the father of the child over the baby as it sleeps is also said to be a preventative.
DS9: "Chimera" 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 USS Defiant in an alternate timeline in DS9: "Children of Time", that would indicate Changelings could live for at least four hundred years.
Vocal Replication: All Changelings can mimic any sound they hears using their voice. Voice Manipulation: All Changelings can freely manipulate their voice, allowing them to control their voices to imitate sounds of creatures such as animal noises and explosions or increase or decrease the tone of their voice.
Some types of octopus, squid, and crustaceans have blue blood. Their blood contains a high concentration of copper. When copper mixes with oxygen, it gives their blood its blue color. Blue and red are not the only possible colors of blood — some animals bleed green.
Blue Blood is a deep, neutral, Caribbean aqua with a turquoise undertone.