No sooner had those words left your lips, there's a tugging sensation in your coccyx. Looking behind you, you see a lump start growing.
The skin began to turn a deep red as a long whiplike tail wriggled out of your spine. It starts swishing as new nerves and muscles come to life and the tip splays into a sharp spade
The skin all over your body start to turn a firery red, as strange black patterns like tattoos begin to cross here and there, etched into your skin almost like runes. The bones in your hands crunched as your palms thicken and you gain short little claws on your fingers. You feel a sudden wrenching as two batlike wings suddenly sprout from your back, unfurling to their full width as they flap. Your legs began to change, along with your feet. Your toes meld together until you only have three of them, claws grow from the tips as the bottoms become thicker.
Your ears twitch as they grow to points, your hair falls out leaving you bald but soon a pair of small horns grows from your scalp and a long trail of spines grows down from your head all the way down to the top of your tail like a long mowhawk of ridges.
The changes crept up the bridge of your nose as your face began to change, you could feel it shift though you dont see it, your nose broadens, teeth sharpen. The features of your face start to resemble those you had when you were just a young girl of ten, but now dark red and twisted with the strange runic tattoos all over them. Short but sharp teeth replace your former ones. Golden rings peirce your ears, your nose, and belly button. Heavy metal bangles latch themselves to your wrists and feet, and more gold and metal bangles appear on your tail.
Then your body trembled, and your clothes grow bigger and looser as you got shorter and smaller. Stepping out of your clothes, you glanced over at the book of myth lying open on the floor. Wow, that thing was legit! And this was only a lesser monster!
Flexing your clawed fingers, you think it wouldn't hurt to take a gander at your new form. Heck, maybe try out another spell from your book!