Trans-Species Transformation

Cross-Species Transfiguration is a branch of Transfiguration in which one animal is Transfigured into another. It is a basic O.W.L. spell and is taught to fourth-years and above at Hogwarts School of Witchcraft and Wizardry. The spell seems to be easier if the animals in question have similar names, e.g. guinea fowl to guinea pigs.

Although humans are creatures too, it is harder to Transfigure a human into an animal, especially Self-Transfiguration, and so this is not taught until sixth-year. There is a distinct difference between an Animagus and Self-Transfiguration, the difference being that an Animagus is a rare wizard with the ability to transform into an animal at will. Self-Transfiguration is simply Transfiguring oneself into another form, and so a wand is necessary to perform the precedure, and can be performed by any wizard skilled enough.

Known instances of Cross-Species Transfiguration

 * Circe, a witch who lived in ancient times, was famous for turning sailors into pigs.
 * According to legend, after Quintius MacBoon, head of the MacBoon clan, killed the head of a the rival McClivert clan, Dugald McClivert, in a drunken duel, the MacBoons was attacked by the McCliverts and the entire family was Transfigured into Quintapeds.
 * During the Quidditch World Cup of 1474, all 700 fouls were commited, including one of the players Transfiguring one of the Chasers on the opposite team into a polecat.
 * During the 1600s, Thaddeus Thurkell had seven sons, all of whom were Squibs. Thurkell was so angry he Transfigured them all into hedgehogs.
 * During the 1800s, it is possible that Mirabella Plunkett Transfigured herself into a haddock in order to live with her merman lover, although it may be possible that she was an Animagus.
 * In 1991, Rubeus Hagrid attempts to turn Dudley Dursley into a pig, however, only gives him a pig's tail.
 * D.J. Prod stated that he was able to turn his wife into a yak after he took a Kwikspell course.
 * In 1992, a Hogwarts student accidently changed his classmate into a badger.
 * In 1994, Fred and George Weasley invented the Canary Cream, a prank item which, when eaten, automatically Transfigures the eater into a large canary, which they used on Neville Longbottom,
 * In 1995, Draco Malfoy was Transfigured into a ferret by Alastor Moody as punishment for attempting to attack Harry Potter while his back was turned.
 * In 1995, fourth-year Hogwarts students Transfigure guinea fowl into guinea pigs.
 * While competing in the second task of the Triwizard Tournament in 1996, Viktor Krum attempted to Transfigure himself into a shark, however, he only Transfigured his head and misplaced the shark's teeth.
 * In 1996, Hannah Abbott accidently Transfigured her ferret into a flock of flamingos in her Transfiguration O.W.L. exam.
 * Gwenog Jones, captain of the Holyhead Harpies, was particularly skilled at Transfiguring anyone who disagreed with her into woodlice.
 * During the Battle of Hogwarts in 1997, Percy Weasley shot a Transfiguration-based jinx at Pius Thicknesse, Transfiguring him into some sort of sea urchin.
 * Many examples of Cross-Species Transfiguration are seen in the Harry Potter video games, including turning Blast-Ended Skrewts into ducklings and ravens, Dugbogs into ravens, Salamanders into rabbits, Vampyr Mosps into worms and Erklings into geese and chickens.

Practioners of Cross-Species Transfiguration

 * Circe
 * The MacBoon clan
 * Thaddeus Thurkell
 * Mirabella Plunkett
 * Rubeus Hagrid
 * D.J. Prod
 * Fred Weasley
 * George Weasley
 * Alastor Moody
 * Viktor Krum
 * Hannah Abbott
 * Gwenog Jones
 * Percy Weasley

Known Cross-Species Transfiguration spells

 * Avifors: Turns Dugbogs or Blast-Ended Skrewts into a flock of ravens, seen in Harry Potter and the Goblet of Fire (video game).
 * Ducklifors: Turns Blast-Ended Skrewts into ducklings, seen in Harry Potter and the Goblet of Fire (video game).
 * Lapifors: Turns target creature into a group of rabbits, seen in Harry Potter and the Prisoner of Azkaban (video game) and Harry Potter and the Goblet of Fire (video game).
 * Piscifors: Turns target creature into a fish, mentioned in Harry Potter and the Goblet of Fire (video game).
 * Pullus: Turns Erklings into geese, seen in Harry Potter and the Goblet of Fire (video game).
 * Vermiculus: Turns Vampyr Mosps into worms, seen in Harry Potter and the Goblet of Fire (video game).

Appearances

 * Harry Potter and the Philosopher's Stone
 * Harry Potter and the Philosopher's Stone (film)
 * Harry Potter and the Philosopher's Stone (video game) 
 * Harry Potter and the Chamber of Secrets
 * Harry Potter and the Chamber of Secrets (video game)
 * Harry Potter and the Prisoner of Azkaban (video game)
 * Harry Potter and the Goblet of Fire
 * Harry Potter and the Goblet of Fire (film)
 * Harry Potter and the Goblet of Fire (video game)
 * Harry Potter and the Order of the Phoenix
 * Harry Potter and the Deathly Hallows
 * Fantastic Beasts and Where to Find Them
 * Quidditch Through the Ages