Frankie Foster is one of the few people living inside the Foster's home, a place known for welcoming imaginary friends. While a bit grumpy at times due to her age, for the most part Frankie is a patient, loving, really fun and lovely person, specially with her friends. It is unsure how, likely due to the power of imagination of the place, but she is able to swallow whole things just as big as herself, great for someone who loves cookies. She has yet to swallow a living being or person... Yet.