Aphasia was the daughter of Serif (who had made modifications to her) and the mother of Hoff, and appeared as a young girl with a balloon, which she was connected to. She could command the balloon to pursue and kill people, and when Bernice Summerfield popped it, Aphasia fell screaming in pain. She had a hidden pouch in her wrist where she concealed black capsules that released lethal gas.
As an Aubertide, Aphasia ate meat, trying to catch the cat Wolsey and later eating a sparrow. She later ate a nurse to assume her form when weakened, afterwards discarding it to become a girl again. Her personality was psychopathic, wanting to look into the Time Vortex so she could see horrible things, shooting a stone Gargoyle because she hated gargoyles, and being interested in watching Greeneye's sexual conquests.
During the Dubraxine assult on Hulton College to obtain the biodata pod containing the Doctor's Time Lord DNA, students lead by Rocastle shot and killed Aphasia, who tried to release another gas capsule in her final moments but failed. Enraged, the rest of her family followed ceremony and ate her entire body, using a fusion bomb to turn the entire school to glass as a tomb for her. Timothy Dean later showed John Smith the possible future of a Gallifrey taken over by the Aubertides, where a statue had been erected in memory of Aphasia. As Smith helped the Doctor become himself again, this future was averted. (PROSE: Human Nature)