Not much is revealed about her past, other than the fact that she was once acquainted with writer Cuddlywhiskers. From her brief appearance, it's assumed that she and Cuddly had a sexually aggressive relationship, as she's first seen behaving like a maid, which is followed by a lusty bout of disobedience after being yelled at by Cuddly.
What is known is how she met BoJack, as she was bringing some water to Cuddlywhiskers and BoJack, prompting Cuddly to introduce her.
She's very reserved and intelligent, possessing a very high opinion of herself, as well as a persistant, and demanding presence, seen when she apparently continuously contacted BoJack to remind him of something when her deadline wasn't met, and refusing to stop until it was finished.
She is shown to be very sexually motivated, as shown with her former relationship with Cuddlywhiskers, as well as her repeated attempts to have BoJack retrieve a graphically sexual letter she wrote to Cuddlywhiskers for "sentimental" reasons.
She is shown to have a softer side, as shown in her own self-indulgence, as she knitted herself a spider-silk sweater, and in her interactions with Cuddlywhiskers, where she's seen putting on an act to seduce him.
As a black widow spider, she has a less humanoid appearance than most of the show's animal characters.
She may possibly be bald. Possessing eight eyes in anatomically correct positions for a widow spider, complete with lavender or indigo eyeliner on each, lush lips with magenta or blue lipstick, sharp teeth and what appear to be two sets of pedipalps on her face. She has grey skin and a red hourglass on her chest. She has six long arms and two legs, matching the limb count of a spider. Her build is very mechanical, having a broad body shape, while also possessing thin limbs. Despite this, her waist is very large, as widow spiders have very big abdomens when compared to their heads.
Clothing-wise, in her first appearance, she's seen wearing clothing that could be considered "in style" in 2007. This outfit consists of a dull, greyish-burgundy wig styled into a bun, a pink sweater-jacket with a tied lace, a dark lavender skirt with thin white likes on it, a fuchsia belt, and matching fuchsia high heels. As mentioned before, she wears lavender eyeliner, and magenta lipstick.
In 2016, she's seen with a new attire more in-line with modern hipster-esque tropes involved. She wears a fuchsia berret, a black long-sleeved top with a white lace-plaid patter on it and a deep violet belt. Her skirt is obscured by the table in the scenes she's in. As mentioned before, she has blue eyeliner and indigo lipstick. Later on in the episode, she's shown finishing a pink sweater, which she eagerly puts on.