Squeak

Squeak was the younger sister of Midge, a human who had been transported to the Cheetah World and she was infected by the virus. This meant that he would become feral. He transported the Doctor's arch enemy the Master to Earth following his infection, teleporting the Time Lord with him. She was upset when Midge killed her cat and was crying about it when Ace and the Doctor walked in on her. Ace then took her to her nan's flat which was upstairs. (DW: Survival)