The magic of Peluna can be simplified in one statement: It is the manipulation of external magic using the unique reaction of a creature's internal magic. This can manifest in many ways, from the manipulation of states of matter (solids to liquids and back without changing temperature), manipulation of temperature (freezing touches or boiling breath), manipulation of energy (electricity being a common example), and even more specific connections to pure elements themselves (control of air, water particles, and many types of rock being a few examples). This makes it difficult to place certain types of magic into categories, seeing as some creatures may have different approaches with similar (or sometimes the exact same) outcome. One example of this is walking on liquid surfaces. One creature may have a freezing touch that can chill any liquid into a solid state, reverting it back when they move away. Another may be able to manipulate that liquid to the point it's compacted into a hard surface beneath their feet. A third may even be capable of changing the state of matter of the liquid, making it a solid until they pass over the liquid. They are different approaches, but all yield the same result; The creature crossing over the liquid simply by walking on it.
While this magic is difficult to put into categories, it has been noted some "outcomes" are commonly found among certain species. For example, the manipulation of liquifying solids into a liquid state without changing the temperature of the solid can often be found in ferrets. Not all ferrets will have this ability, but a notable group of solid-liquid manipulators are ferrets. This can extend to other mustelidae, with polecats, martens, weasels, and minks finding they too have a large group of solid-liquid manipulators among their own species. This doesn't necessarily mean all mustelidae are in this position, however. Badgers, wolverines, and skunks, while part of the family, don't often find themselves included among the solid-liquid users. This also isn't necessarily exclusive to mustelidae, as many members of the felis genus (domestic cats, black-footed cats, sand cats, etc) are in the same position as ferrets.
Essentially, while these magical outcomes may have a sort of "preference" for these species, they can bleed over into other creatures in Peluna. It's entirely possible to find a polar bear that can turn stone to liquid to help fix holes in their homes, or a house cat that can freeze their water cups (usually before inevitably knocking them off a table). In short, it isn't necessarily a strict rule that all these creatures will have this one type of magic if they are a specific creature. There are just enough for it to be a notable trend.
Shapeshifting is often used as a blanket term for magic users who use their abilities to alter themselves instead of their environment. This can range from changing the color of their fur/scales to fully changing their species. There are limitations, of course. The pattern of their coat/bodies will always translate to new forms, with only minor alterations to adjust to additions/loss of limbs or appendages between species (for example, a cat to a spider, or a cat to a snake). Eye color will also remain the same, though this is more of a social rule than that of magic itself. Shapeshifters can often be put into two categories; Minor shifters and Major shifters.
Minor shifters are, in essence, minor. They only make minute changes to themselves, such as changing the color of their forms to lengthening limbs. Those who were born with other forms of magic that make shapeshifting an adjacent ability often fall into this category. They almost never change their species, with the most extreme examples being canids who lengthen their snouts or felidae who change their ears to appear like other breeds of the same species. Those who change the features of other creatures are often debated as to whether they fall into this category, with some individuals claiming they don't count since they don't alter themselves. Others claim they do because they're still altering a living creature, just like shapeshifters. Some simply say they'll count if they also change themselves. Most minor shifters will welcome anyone who can change others into their circle, regardless of whether they change themselves or not.
Major shifters are the other end of the spectrum. Instead of changing just their coat, they'll go so far as to change their entire species. It often starts with an adjacent form to what they were born as, such as a snowshoe cat turning into a mainecoon. With enough practice, and understanding of the creatures they wish to turn into, some more experienced major shifters can transform into distant complex creatures, such as dragons, phoenixes, or dinosaurs. It takes thorough research, planning, practice, and sometimes even "stepping stone" shifts to get to that point. For example, a mouse trying to turn into a horse may hop to forms closer to their current form the form they've set as their end goal, such as rabbits, deer, and dogs. These shifters are often born with this magic, though some who have taken up shapeshifting as an adjacent practice have managed to succeed as major shifters. Mastered forms are often kept on standby in a major shifter's mind, be it to show off or to shift to if they feel the need to be one of those creatures.
All who know about shapeshifting magic will have heard of why this is a rare field of magic to pursue. Major or minor, shapeshifting takes a great deal of focus to get right. One needs to know what the end goal is, and what they're starting with, to have a clear shot at performing such a change properly. It also takes a great deal of concentration, with the shapeshifter using the knowledge they have to ensure each step of the change is done correctly. Many just leave it at that, at least among shapeshifters themselves. Those outside the community, however, are likely more well-versed in the other reason not to rush into this field. If a shapeshifter is lucky when they shift unprepared, or panic mid-transformation, they'll only have feathers where there should be scales, or wings that are just short of what it takes to fly. If not... Well, many cryptid stories exist in Peluna, with shapeshifters being the only ones who truly know that most of them are because one of their own bit off more than they could chew. To outsiders not let into the loop by shapeshifters, it's just a story of a strange long fox with scales and gills in the nearby river, or an odd hooved amalgamation of deer, horse, hound, and dragon racing along mountain passes. To shapeshifters, it's a reminder to take things slow, breath, and remember what they once were. That way, if they do find themselves just sideways of what they were meant to be, they can retrace their steps and return to familiar ground. All they need to do is breath, clear their mind, then turn back into something they know well.