A required class, compulsory until O.W.L., taught at Hogwarts School of Witchcraft and Wizardry, Transfiguraton was the art of turning one thing into another, changing the form and appearance of an object by altering its very molecular structure. Known as a complex and occasionally dangerous practice, Transfiguration required accurate wand skills and required lots of practice. Whilst at HogwartsHarry Potter and his friends were taught by Minerva McGonagall.