Saibra

 was a mutant human who would replicate a person when touching any part of their organic matter.

As she was unable to control this ability, she helped the Twelfth Doctor rob the Bank of Karabraxos in order to gain a gene suppressant which would remove her powers. During the mission, she briefly impersonated Clara Oswald to demonstrate her power and impersonated a businessman named Mr Porrima to facilitate entering the bank, before copying a security guard to rescue the Doctor and Clara after they were captured. After the mission was successfully completed, Saibra shared a takeaway with the others before being returned to her own time and place, having used the gene suppressant. (TV: Time Heist)