Sandy wears a yellow dress with flowers on it. Her father was killed by a band of raiders, but before she could be killed, she was saved by a pack of deathclaws. The deathclaws brought her and her mother to Vault 13 where she has remained under the watchful (and often controlling, as Sandy seems to imply) eye of her mother.
Sandy states that she enjoys getting piggyback rides from Valdis, one of the deathclaw guards. She also likes to pretend that she is a cat, and the Chosen One can humorously join in by pretending to be a dog if his/her Intelligence is less than four.