Shona McCullough

Shona McCullough was a woman who worked in a shop. She had an itinerary for Christmas Day which included forgiving someone called Dave and watching DVDs of Alien, The Thing from Another World, Miracle on 34th Street, (TV: Last Christmas) and a rerun of her guilty pleasure Santa Claus: The Movie (PROSE: Ian the Elf) along with watching a Thrones marathon.

She was attacked by a dream crab and in her dream state, she thought she was a scientist at the North Pole on Christmas Eve. She took point and used a song and dance to Merry Xmas Everybody to avoid thinking of the crabs. 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. Santa used My Little Pony to instigate a reaction from her.

After waking up and being disgusted by the dying dream crab, Shona checked off "forgive Dave" on her itinerary. (TV: Last Christmas)

Behind the scenes
Shona was intended to be the next companion, had actor Jenna Coleman decided to quit her role as Clara Oswald after Last Christmas.