Mark sat down on the examination table. The doctor prepared the needles. "You're sure you want to do this?" He asked. "Once I inject you, there's no changing back for at least a week." He informed him.
"Yes, I'm ready." Mark replied. Mark and his girlfriend Tasha had always wanted a dog, there was only one problem. Mark was really allergic to dogs. So once transformation serums were introduced and showed that people transformed wouldn't be effected by what they changed into, Mark and Tasha saw their chance.
Mark signed up and the day had finally come. The doctor walked over to Mark and gave him the shot.

Mark felt a his spine alter as his tail grew out, longer and longer. He started wagging it around. "This won't affect how I think right?" He asked the doctor. "No, you'll still be able to think like a human but you won't be able to talk. You might also notice a little bit of dog traits like barking at a doorbell but you won't have a full dog brain." He responded.

Mark's ears started turning to a point and moving up to the top of his head. His hearing went away for a bit but came back stronger than ever. Color started to fade from his vision was his eyes changed. His tongue got bigger and filled his mouth and became slobbery. His face started pushing out, his teeth sharpened, and his nose connected to his snout and started turning black and his sense of smell increased. "You might want to get down on all fours for this next part." The doctor said to him.

Mark did as he suggested just in time as his back legs started shrinking to give him a balanced body. His thumbs started moving up his arm a bit until they turned into nails. His pinky and ring finger merged into one as his hangs became paws. He flipped over his hands to see little areas bubble up and become his pads. His bones rearranged and he was unable to bend his front or back paws that much anymore.

"Where's my Fur?" Mark asked, waiting. "Oh, the gender change has to happen first." The doctor responded. "What! I didn't put on the form for a gender change!" Mark said. "Someone did," The doctor said, showing him the form. Written in his girlfriend's handwriting was a request for a gender change. Mark knew he couldn't do anything now so he just accepted his fate.

He felt his penis start shrinking and his asshole move up and change to that fitting of a dog. His testicles shrank into his body as his female dog parts grew in. His nipples grew a little as three more pairs went down his body. Finally her coat of fur grew in, identifying her as a German Shepard.

Tasha walked into find a not so happy female Mark sitting there. "Oh I know you aren't happy but I know what will cheer you up." She held up a leash and Mark's expression changed. "Want to go for a walk?"