Baby Sister

Baby Sister is a female infant who lives in the town of Harvest. Like Mom, her real name is unknown.

History
Baby Sister can be found sleeping in her cot from the start of the game, in the kitchen. When talking to Mom for the first time, she mentions to Steve that he should not wake up his sister. After Steve somewhat loudly questions the fact that he has a sister, a cutscene will show Baby Sister sleeping in her cot. On the sheet next to her a wasp is seen injecting its eggs into a spider it killed. Upon being woken up, Baby Sister will begin crying and Mom will go to console her. Upon doing so, she notices that the baby accidentally ate the spider, causing Mom to get angry and swat the wasp away. She demands to Steve that he march over to Tetsua Crumb's house and tell her off for not keeping a check on her wasps. When Saturday arrives, Mom will talk about feeling useless since the bake sale is over, during which time Baby Sister begins crying. A cutscene then shows her eyes popping out of their sockets and the young wasps flying out of her. Mom will flick away a baby wasp and push one of the eyes back in, causing some blood to fly out of the socket and splatter on Mom's face, which she will then lick off. Mom will then remember that she can still look after her infant child and, no longer feeling useless, her mood improves instantly.

Trivia

 * Baby Sister is one of the three only characters in the game that cannot be killed, the others being Hank and the Sergeant-at-arms.
 * Killing Tetsua Crumb has no effect on Mom's dialogue during the second cutscene with Baby Sister, as Mom will still demand Steve to tell her off.