Noodle Incident: Janet recalls an incident in which George, who had not been on Earth for so long, went around sniffing people's bottoms like a dog.
Speaks Fluent Animal: George uses a device called the Interspecies Interpreter that allows him to talk to animals (except dung beetles, as George says "why would you want to, they live in dung"), specifically Ella and Stanley's dog.
The Thing That Would Not Leave: Mrs Raven basically becomes this for Doctor Crispin when her attitude finally drives him to fire her. Not only does she delay the arrival of her replacement, but she keeps coming in to the health centre every day, feigning illness and driving other patients away. Since Piers can't take her to court to make her leave as she knows too many details about his history for him to be sure she wouldn't ruin his career if he tried to sue her, he's eventually forced to re-hire her.
