McCaitlyn is a female Asian Tiger Mosquito. She has pink eyes and blue transluscent wings.
She is seen wearing a cropped navy long-sleeved shirt with red trim at the collar and white stripes at the sleeves, a pair of leggings with fishnet cutouts, and navy high-heeled boots.
Little is known about McCaitlyn's personality.
McCaitlyn is a friend of Jameson H.'s who sneaks her water bottles filled with vodka on visiting days.
In A Horse Walks into a Rehab, BoJack hears Jameson jumping out the window. He realizes she was trying to escape and catches up to her. Jameson says her friend McCaitlyn told her, that Jameson's boyfriend Dathan was going to break up with her because she got fat junior year of high school. Jameson says she needs to show him she's hot again, get back together with him, and show him how shallow he's being. BoJack says she does not need to do that.
BoJack decides to go with her, as he was the one who gave Jameson advice on how to escape. They wind up at Dathan's house party. BoJack says they should not go in as the house looks trashed, and there are drunk teenagers everywhere. Jameson says she'll find Dathan, and crush him with her thigh gap, and then they can leave the party. Jameson calls out for Dathan.
BoJack hears Jameson screaming. She caught McCaitlyn and Dathan making out on the couch.
BoJack then comforts a crying Jameson on the sidewalk, reminding her she was going to break up with her ex anyway. He also tells her that her friend sucks. Jameson says they are right and she is a mess.
BoJack tells her she does not need to drink alcohol, she needs to go back to rehab and sleep there. Jameson says she'll go to her real home and sleep in her own bed. She says when her father discovers her, asking why she's not at rehab, she'll retort by asking him why he doesn't go to rehab for being a terrible father.
BoJack tells her to come back to Pastiches as she promised. He then tells her, if she really wants to go to her dad's, she can steal Dathon's car. Before BoJack can even finish his sentence, Jameson is already driving off.