Mabel is the orange pet bori (http://bookofages.jellyneo.net/species/bori/) of Mushroom and Jack, who hatched, along with her flatmates, from eggs that came from a portal accidentally activated by Mushroom.
She is very friendly.
Her first word was "whoopsie-daisy".
She is determined, busy and predictable. Mabel seems to notice everything around her; she makes an excellent sleuth, picking up on every little nuance. She also prefers to be clean and likes to be in control, to the point of occasionally seeming "bossy".
She likes to do the right thing.
She also likes to analyze new things before leaping into them.