Metamorphosymbiosis

Metamorphosymbiosis (or Metamorphosimbiosis) is a type of magic introduced in Season 1.

Overview
Metamorphosymbiosis is a type of magic which allows the user to transform oneself and others into other living beings, such as insects, or to just generally change one's appearance. It is often used interchangeably with the word “metamorphosis” in the series. At Alfea, metamorphosymbiosis is taught by Professor Wizgiz primarily during a fairy's freshman year. One kind of metamorphosymbiosis important to the plot of Season 7 is Wild Magic.

Trivia

 * Metamorphosymbiosis is made of two words:
 * "Metamorphosis", which is defined as "a transformation".
 * “Symbiosis”, which is defined as “a mutually beneficial relationship between two creatures”.