Jesse is a Shlorpian, an alien species which originates from a planet called Shlorp. She has a primarily light green complexion, save for a few dark green speckles on her forehead. Jesse is usually seen wearing a pink dress with white polka dots, white slip-on shoes, and a reddish bow atop her head. She is the only female in her family; a fact which becomes relevant in "The P.A.T.R.I.C.I.A. Device", wherein she has to do a project for school on women's rights.
Unlike Yumyulack, she is optimistic, free-spirited, and compassionate, much like Terry. Jesse enjoys talking to people and finding the positive attributes of life on Earth.
She is worshipped in the wall as a saint as her periodic habit of throwing candy and other odds and ends into the wall out of pity is primary source of "supplies" for the people of the wall.
She gets along well with Terry due to their similar interests and dispositions. Though she spends most of her time with Yumyulack
Jesse and Yumyulack disagree on subjects like humans, as the latter has a wall he keeps them in, but they still seem to care for each other. Jesse took Yumyulack to the hospital when an accident occurred and was visibly worried when the doctors were working on him, and later said "thanks for not dying!" She once did go along with Yumyulack’s shrinking and eventual lobotomizing of their classmate Lydia due to bullying. Jesse may have little patience for bullies.
- According to Yumyulack she "chose" to be a girl when they were created