He opens the Book of Beast, thinks for a moment and says:"Yes, I think you'll be quite loyal like this..." He utters the command, and for a moment you feel a bit of a shock as the spell washes over you, whichever it may be. At first you don't notice anything happening, and ask:"What have you done to mrree?" As you finish this sentence, you notice more of a growl starts entering your voice. Your face starts hurting and stretching, mouth feeling numb with canine teeth and tongue growing. Your lips and nose flatten out, the latter becoming darker and wet. You try to say something, but all you can produce is barking. The man grins:"Hehe...good boy." You can look across your muzzle when you look crosseyed now, and it's colorful fur starts spreading across the rest of your face. Feeling a bit of burning in your eyes, they suddenly become capable of nothing but monochrome, and your ears feel like they're melting a bit, now hanging down the sides of your head.
All across your body the fur spreads now, showing blobs of white, brown and black fur; the almost unmistakable markings of a beagle. At least you don't feel as cold anymore as when you were naked, but this still creeps you out. Your tied hands and feet shrink and swell, the fingers and toes quickly disappearing into your forming paws, pads forming on the palms and soles. Suddenly, your arms and legs twist around into a new configuration, and you yelp in pain as you feel your arms twisting. "Release him", the man commands his assistant, "we wouldn't want him to break his forepaws right away." The silent figure obeys and slashes your ropes with a claw, making your fore- and hindlegs spring into a quadrupedal position. You shakily balance on your malformed semi-human body, trying to stand on paws, when you feel a new pain coming on. Extending from your spine, the pain quickly manifests itself as a smooth-furred tail extending from it, automatically beating back and forth as it develops.
As the changes seem to finish, your body feels as it is compressing inwards, changing your proportions to that of a normal beagle and allowing you to stand in a normal dog's position. You softly whine at how big the man now is, but he is already quick to bend down to you with something in hand. Around your furry neck, he straps a small collar with a leash ring and a silver heart pendant. You look at him in confusion while he strokes your back:"Now, what shall we do with you?"