An Animagus is a witch or wizard with the ability to transform themself into a specific animal (and back), A registration exists to track those with this skill.
Unlike a Metamorphmagus, practise, skill, and patience are required for one to obtain the ability. The process of becoming an Animagus is strenuous and takes a long time to complete. Beyond the tedious nature of the process, it also has a chance of causing a permanent half-human/half-animal transformation.
The person attempting to become an Animagus must first keep a mandrake leaf in their mouth from full moon to full moon (one month). If the leaf is at any time removed from the mouth, or swallowed, the person must start the process over again at the next full moon. Once the month has passed, if the full moon is not visible, the process must be started over. Otherwise, the next step requires the leaf be spat into a phial in the pure rays of the moon. Then, the wizard must ass their own hair to the phial, along with a silver teaspoon of dew which has been untouched by sunlight and human feet for seven days, along with a Death’s-head moth chrysalis. After mixed together, the mixture must remain undisturbed in a dark and quiet location. The wizard then must wait for the next electrical storm to occur, and while waiting for this to happen must say “Amato Animo Animato Animagus” while the tip of their wand is over their heart every day at sunrise and at sunset. When an electrical storm occurs, the wizard then must immediately move to a large and secure location, and recite the incantation again. Then drink the Animagus Potion.
If successful, the Animagus will now be able to transform into an animal and back at will, without the use of a wand. The animal an Animagus transforms into is based on the wizard’s personality and their inner-traits, while the exact way this occurs is unknown, but may be similar to how one’s Patronus form is chosen, as there are Animagi whose Patronus is the same animal as their Animagus form. While in Animagus form, certain distinguishing marks on the wizard are visable, this could be either a physical trait, such as a scar, or an acquired one, such as glasses. On the Animagus Registry, the type of animal and distinguishing markings are kept as part of public record, so Animagi do not abuse their abilities.
Animagus is a portmanteau of the word “animal” and the Greek word for wizard, “magus.”
Can you choose your Animagus?
A persons generally cannot choose their animagus as it reflects the casters’ inner most personality traits.
How many Animagi are there?
Technically there are only seven animagi registered in the entire twentieth century. However, we know of at least four unregistered animagi in the wizarding world including Peter Pettigrew who can transform into a rat, Sirius Black who can turn into a dog, James Potter who can transform into a stag and Rita Skeeter who can turn into a beetle. Even though it is illegal to become an animagi without registering, the magical world will never know for sure how many unregistered animagi are sneaking around the magical world.
Is your Animagus your Patronus?
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. A person’s animagus is said to be the same their entire lives, however, there have been cases that a person went through a tramatic experience and their patronus changed, like when Tonks’ patronus changed to a wolf after falling in love with Lupin. Due to the limited number of witches and wizards that are registered animagi, there is not enough evidence to conclusively determine if they are usually the same or not.