Beth Normal

Beth Normal is the three year-old daughter of Melissa Normal, little sister of Peter, and granddaughter of Seamus Flannagan.

Personality
Beth is a very fussy and spoiled bratty toddler who constantly wears her favorite Strawberry Shortcake bathing suit no matter what, and absolutely refuses to take it off, even if her mother tells her to unless it's to have it washed.

She speaks in a babyish voice and likes to tease or otherwise be difficult for her big brother Peter and his friend Dill Bodinksi, and most often gets away with her behavior because her mother indulges her.

Volume 3: The Changeling
Beth is left to be babysat by Peter and Dill while Melissa goes to a job interview. Due to not being happy about it, Beth screamed her head off endlessly. Peter tried bribing her to stop screaming with an ice-cream sandwich ,but it didn't work. Dill tried to scare her by pretending he was gonna sit on her, but she literally kicked him in the butt and made him fall flat on his face.

Afterwards, when Beth touches some strange mushrooms she disappears.

For a short while, Peter and Dill fear Beth might have gone missing until they find "her" a minute later. Only now "Beth" is acting nice and sweet and well-behaved. But then she continues to exhibit more strange behavior, such as growling at Peter when he tries to change her training pants and hitting Dill on the head with a wooden spoon while expressing no emotion, eats a whole apple in only two bites and spits out the stem before letting out a window-rattling BURP, and even eats a whole jar of peanut butter, and even eats plastic plates before she upchucks a tennis ball-sized hunk of plastic.

Before long, Peter and Dill realize this isn't Beth at all when "she" turns green and smiles a smile full of long, yellow, and dagger-like teeth that couldn't possibly be in the mouth of a human toddler, and then lets out a terrifying ROAR and starts crawling on the ceiling. She chases Peter and Dill into Grandfather's study and they remain there, trying to figure out what has become of Beth.

There, Peter comes across a book titled "Fairieland: Portals To The Other World and Its Denizens" and figures out that "Beth is not Beth but rather it is a Changeling! Earlier, Beth had stepped into a ring of mushrooms outside, which were actually a Fairie Ring, a gateway to fairieland, and thus was switched with a changeling.