Olive the rabbit is an NPC in the Fields.
Her references to cereal indicate she is a parody of the rabbit Tricks, the mascot for Trix cereal.
This character may have been named after Olivia mentioned in the Credits.
Olive: Hi, I'm Olive the rabbit.
Olive: I have so much cereal left to eat! I love cereal.
Olive: The box is so big. It never ends!
Olive: Neverending cereal!
Olive: Hmmm...maybe that's not such a bad thing.