Chap 11
As soon as Araminta said 'Animagus' she felt her body start to change. Her arms and legs lengthened, and her eyes moved apart. Her hair stuck out behind her and she felt her forehead grow to a point.
Araminta felt herself lean forward, then heard the clip-clop of her...hooves?...on the floor. "What's happening?" she tried to say, but all that came out was a high whinny."
"You're a unicorn," said Professor McGonagall. "See?" She Transfigured the chalkboard into a mirror and Araminta saw herself fully. Her silvery mane swung from side to side as she tossed her head and pranced up to look.
When Araminta tried to talk, she couldn't, and she became very worried. She stamped her feet against the floor.
"There, there," said Professor McGonagall. She put her arms around Araminta. "Concentrate and say Finite Incantatem to yourself, and you'll be back to normal in no time."
With a pop, Araminta fell to the floor in her regular body. "How did that happen? I can't be--I can't be a unicorn!"
Professor McGonagall rummaged in her desk for a tin of ginger biscuits. "Of course you can. Actually, everyone can, if their magic is strong enough, up until the time they--well, up until the time they lose their virginity. Then their Animagus form is different, and reflects who they are as an adult. You don't hear of children turning into unicorns very often because most don't have your advanced magical skill."
"Oh," was all Araminta could think of to say.
"Also, the Animagus spell is very difficult, even for adults, so not everyone learns to find their inner animal. You may never find out what your adult Animagus form is." She stopped speaking to give Araminta a stern look. "And, in any case, you should wait some time before you try to find out."
Araminta decided that McGonagall was talking about more than just trying out spells. She thought about Blake, and decided that she could wait a little longer. She was puzzled about one other thing, though.
"Professor? How did you know that I was a strong enough witch to do the spell?
A broad smile lit up the Transfiguration professor's face. "Well, you remind me of a girl I used to know. Hurry, now, or you'll be late for Potions!"