Cindy Campbell is an American extraterrestrial researcher who can speak English and Japanese. She is interested in studying Squid Girl because she believes she is an alien. She pesters Squid Girl in the hope that Squid Girl will accept being studied by her. She also works with three researchers named Harris, Clark, and Martin. She has blonde hair that reaches her back. She is usually seen with her bikini and short red sweater. She once came by the Aizawa's home to teach Takeru and Squid Girl to speak English, and Squid Girl quickly grasps it, with Eiko misunderstanding entirely.