You run away from the man who's now a dragon as a blast of fire lands right where you were standing. You make it back to the book, as the dragon prepares another firebreath.
You can't carry the book around in this form, but don't stand a chance without it. Yet at the same time, you doubt you're be able to dodge his attacks easily as a human. You need a different spell.
You try the first spell you find that might be useful.
"Half!" You meow the command word, and in a poof of smoke, you transform into an anthropomorphic cat. There were probaly better animals you could have chosen, but right now you were just trying to get thumbs back. You quickly grab the book, and proceed to run, as another blast of fire lands behind you.
You look through the spellbook looking for a spell to slay the dragon. However, you realize there's a pretty good chance that you're not going succeed on your own. A summoning spell might help, but what real animal could penetrate the dragon's scales.
You decide to try your last trick again. After you dodge his next firebreath, you point at him and shout 'shape' while picturing a mouse.
A cloud of smoke around him indicates a hit, but a second cloud of smoke appears, and out from that walks an anthropomorphic dragon.
"These games are quite entertaining. However, if you're going to fight with spells, so will I."
Things are getting bad. This guy is a much tougher opponent than the thief had been. You're not sure if you can defeat him or not, but he's now intent on killing you so you'd best try. You're also nervous that for every second you don't defeat him someone could show up and see the fight going on.
You have to find a way to end this, and end it fast.