Rona Bellows was a wheelchair user and a grandmother. While waiting for Christmas dinner, she fell asleep and was then attacked by a dream crab. In her dream state, she thought she was a scientist and a professor at the North Pole on Christmas Eve and had use of her legs. She was able to wake up from the crab-induced dream, killing the alien creature in the process, with the help of the Twelfth Doctor and Santa Claus.
The Doctor found her attractive, given that he referred to her as "sexy one" after forgetting her name. (TV: Last Christmas)