Kera-Bera Beast

Kera-Bera Beasts were purple, parasitic creatures. They created illusions to become close to an individual. They fed off that individual before moving on to another. A Kera-Bera Beast stranded on Earth was "adopted" by Betty, who (through an illusion) believed it a Yorkshire Terrier. The Eleventh Doctor and Amy Pond intervened. With a bit of planning, they broke the psychic link. They used a hairdryer at Betty's hairdressers to restore Betty's energy and persuade the Kera-Bera Beast it was actually a cute dog. Betty continued to care for it and keep it for company. (COMIC: The Stray)