Agar

 and Hoyt were Festulasions whose job it was to collect human toes for use as bar snacks.

One Christmas, they captured several people, including the Sixth Doctor and Linda Grainger. They learned, to their shock, that human toes, when removed, didn't grow back, unlike Festulasion toes. Embarrassed, they allowed the Doctor to take them home. (PROSE: She Won't Be Home)