The rare forms include creatures like hippogriffs, unicorns and thestrals, which don't seem like viable Animagus forms. It's not impossible, but it just doesn't seem too plausible that someone could transform into a dragon.
As a pack animal, or as a “lone wolf,” the wolf is a perfect fit for Harry's Animagus form.
In the Harry Potter books, only a few Animagi (registered and unregistered alike) are even mentioned. They are James Potter, Sirius, Wormtail, Skeeter, McGonagall, Talbott Winger, and an unnamed witch who can turn into a cat. The fact that there are so few Animagi just causes us fans to want to know more about them.
Falco Aesalon — Falcon; the first recorded Animagus; the registration system was not in existence in his time.
For example: if Viktor Krum can transfigure his head into a shark's, like he does in Goblet of Fire, that doesn't mean he is an Animagus. Transfiguration is a form of spell-casting, whereas becoming an Animagus is forever. And yes, he could turn into a falcon. Lucky.
Animagus. Lily's animagus form is a Doe, coupling with her husband, James Potter who is a Stag. Severus Snape's animagus is also a Doe.
James Potter
James's Animagus form was that of a stag, which earned him his nickname, Prongs.
Pettigrew's Animagus form was a rat, from which his nickname "Wormtail" was derived. The four friends called themselves the Marauders and designed a map to navigate Hogwarts.
Following both ordeals, Ginny grew into a confident young woman. Her and her friends followed in the footsteps of a previous generation, completely unbeknownst to them, and became Animagi at the age of fourteen, to support their best friend, Maisie Cattermole. Ginny took the form of a grey mare.
Sirius Black and James Potter attended Hogwarts together, and Sirius is Harry's godfather. Sirius is an Animagus, which means he can transform himself into a black, shaggy dog named Padfoot at will.
Draco is not an animagus in the story. However, if he were to become one, I believe he would be a Siamese cat. His belief in his superiority and his snobbish manner line up with Siamese traits, but he, like the cats, loves his family deeply.
Once the initial training is over, an Animagus can change at will, with or without a wand. Animagi who take on the form of species capable of flight can enjoy the sensation without the need of broomsticks, flying carpet, or riding on flying animals.
In the films, Hermione's Patronus is depicted as a European River Otter, and her Animagus form would most likely be the same animal, as confirmed by author J.K. Rowling.
Animagi are extremely rare.
It was debated (but generally believed to be possible) whether one's Animagus form could be a magical creature, and also debated (but generally believed to be impossible) if one's Animagus form could be a Dementor.
Like a wand, the wizard/witch does not choose the animal it becomes. It takes the form of whatever animal matches their personality best. Your Animagus form can be a dragon if you possess the correct qualities, as well as your Patronus.
Usually people turn into Animagi who match their Patronus, so it is safe to assume Snape would be a doe. But based on his morals qualities, I'd say maybe some kind of prey bird; a crow would be the perfect match.
And there is no question that Snape was a talented wizard, and that he could have become one if he had wanted to. But the fact is, there is not one single shred of evidence in Canon that Snape ever became an animagus.
There were only seven Animagi registered in the twentieth century, one being Minerva McGonagall and the other six unknown (PA19). However, there were at least four more that went unregistered by the Ministry: James Potter, Sirius Black, Peter Pettigrew and Rita Skeeter.
Lily began her education at Hogwarts School of Witchcraft and Wizardry in 2019 along with her cousin, Hugo Granger-Weasley, and was sorted into Gryffindor House.
Your animagus is not always your patronus. Both an animagus and a patronus are said to take on a form that reflects the caster's inner most personality traits, so it makes sense that they would be the same. An example of this is that James Potter transformed into a stag and also had a patronus that was a stag.
Was Voldemort an Animagus? No, Voldemort was not an Animagus. He didn't see any reason to become an Animagus despite being a gifted wizard and knowing a lot of magic. This may simply be because his sole purpose was to obtain immortality and become the strongest wizard who could control the world around him.