The doctor injected a serum into Jen's arm. She immediately felt the effects. Her legs fused together at the knees into a 12 foot long mermaid tail. An udder grew just above her pussy. It grew to a tremendous size and filled with milk. Her breasts grew several cup sizes as well. Her hands became fins and a dorsal fin grew from her back. A pair of short horns grew out of the top of her head. Her upper body became covered with cow fur, though her breasts were left bare. She grew another set of breasts. Then some gills appeared on her neck. Jen struggled to breathe. They picked her up and put her in a large fish tank. Then they wheeled her into another room where they hooked her up to a milking machine and wired her pussy.