Heather (The Pilot)

Heather was a student at St Luke's University in the 2010s. She had a defect in her left iris in the shape of a star. She befriended and developed a mutual crush with cafeteria worker Bill Potts.

Heather hated St Luke's and everywhere else she went. She felt this indescribable need to always leave, and go elsewhere. As a result of the defect in her eye she quickly noticed that a strange oil puddle did not properly reflect images like a normal mirror (with left and right flipped), as her face was asymmetrical. She showed the puddle to Bill twice, the second time promising not to go anywhere without her.

The oil puddle absorbed Heather's appearance and thoughts as its "pilot" before Bill could reach them. The combination of Heather's desire to leave and her promise to stay with Bill caused it to obsessively hunt Bill across time and space in the hopes of taking her with it on its travels. When Bill finally freed Heather from her promise not to leave without her, the oil being, piloted by Heather, left to explore the universe. The image of Heather said goodbye to Bill before she let go, and expressed that she liked her, as well.

Bill later expressed regret at having turned down Heather's offer, and knowingly glanced at the TARDIS when the Doctor stated that it was unlikely she would ever see her again. Though initially reluctant, the Doctor allowed Bill to join him in his travels, noting that they may one day find Heather again. (TV: The Pilot)