Guinea fowl to guinea pig

"The guinea-fowl they had been changing into guinea-pigs had been shut away in a large cage on Professor McGonagall's desk (Neville's still had feathers)..."

- After a class on this spell.

Guinea fowl to guinea pig is a Transforming spell that is covered in fourth year Transfiguration classes at Hogwarts School of Witchcraft and Wizardry. It is noted that Neville Longbottom was not particularly skilled with these spells.

Appearances

 * Harry Potter and the Goblet of Fire