She was an elderly lady. Every week, she would transfer into a host's body and take ballet lessons.
One Tuesday in October 2016, she took over the body of Amar Sai and decided to try jumping from a roof as a trial run for a suicide. Tanya Adeola, Charlie Smith and April MacLean saw the boy on the roof and tried to stop her. As a result, Amar's body was left dangling from the roof. This experience persuaded Viola that she didn't like this way of committing a suicide.
After her three-hour period was over, Garry Fletcher, the owner of Joyriders, asked her to help him with a "little problem" by controlling somebody else's body in exchange for two free sessions in the future: he wanted to capture Charlie and Miss Quill to help him with the alien machine. But Mrs Cummings was too upset and asked to be taken back to Barbican Centre.
There her body was taken over by the Coal Hill defenders, who made her run through a building naked and threaten to blow the building sky high with a bomb. Consequently, she was placed on a terrorist watch list and had to serve a lengthy community service plus compulsory counselling sessions. (PROSE: Joyride)