Scotus gave her one of his diet pills, in actuality an alien tapeworm egg. The extreme hunger it caused forced her to gorge herself on "foods" including a Chinese takeaway, a kebab, discarded sandwiches, a pigeon and a dog. She also attacked a man and attacked Toshiko Sato, nearly eating off her face.
Torchwood Three caught and confined her. However, while not being watched she managed to free an arm and chew it off, then died from severe blood loss.
She was aged around 20, and had blonde hair. When encountered by Torchwood, Marianne wore a white silk blouse, brown suede trousers, large silver earrings and a leather jacket. Her clothing was stained with tomato sauce. She also wore a belt which Toshiko thought looked like it was Prada. Her limbs were thin, and her face narrow. She had porcelain fillings in her molars, rather than cheap mercury amalgam. She spoke with a soft Welsh lilt and was incredibly light. (PROSE: Slow Decay)