Kuchi Kopi's origin is unclear but he is most likely a character from an eponymous Japanese series of books. He is described as "a spirit that can be different things to different people" by Bob, a likely reference to the ambiguity and unclear definition of the character.
Kuchi Kopi is first seen in "Crawl Space" where Louise gives Bob her Kuchi Kopi nightlight while he is in the crawl space hiding from Linda's mother Gloria. After Bob realizes he is actually stuck, and Linda realizes he was deliberately hiding from her mother, she makes him stay in there. While stuck in there he starts to lose his mind, talking to the night light and eventually hallucinating that it can talk (among other things). He proceeds to imagine that there is a speakeasy in the walls and that Kuchi Kopi is the bartender, paying homage to the Stanley Kubrick movie, The Shining. Kuchi then starts to persuade Bob to kill Gloria as she is interfering with the restaurant. At the end of the episode when Bob is freed from the wall, Louise and Bob start fighting over the nightlight because Bob refuses to give it back.
During the opening sequence for "Fort Night", Kuchi Kopi appears on a title card which appears for only a couple of frames which reads "Happy Halloween", intended to scare viewers.
In "Flu-ouise", while ill with the flu, Louise asks Linda to bring her the nightlight which is in the bathroom as he is Louise's "doodie buddy". Linda accidentally drops the nightlight in the toilet and water ends up inside of it. Tina suggests the family put the nightlight in the oven with rice to dry it out but they leave it in there too long and it melts, disfiguring it. Louise later swears she will never forgive her family for what they did to her nightlight. But she then goes into a fever state dream where she and the melted Kuchi Kopi go on a Wizard of Oz style adventure to his fortress, meeting some of her other toys along the way that have the voices of her family. The toys sing about how the fortress being built has ruined their day to day lives. It is later revealed that the Kuchi Kopi who Louise travels with is a bad Kuchi Kopi and a good Kuchi Kopi is also occupying the fortress. The good Kuchi Kopi persuades Louise to forgive her family and reveals that the fortress is a metaphor for Louise not forgiving them and closing herself off from them. Bob and Teddy find Louise a new nightlight thanks to Clyde at the About a Toy toy store and Louise wakes up with the new nightlight and forgives the family for what they did.
Kuchi Kopi is a light green spirit-like creature with short stubby arms and cat-like ears. In Bob's hallucination in "Crawl Space" he additionally wears a formal light blue bow tie taking the role of Lloyd the bartender from The Shining.
- Teddy mentions Kuchi Kopi creeps him out when he stays in Louise's room in"Bed and Breakfast".
- Unlike many of Louise's toys, Kuchi Kopi isn't based on any specific Yōkai creature but it's likely that the inspiration came from them.
- Kuchi Kopi is the go-to symbol for insanity or horror in the show. It shows up as a jump scare in the opening of Fort Night, and then later again in "Ambergris" (when Louise begins to talk to the ambergris by nightlight-light).
- At the show's panel at the 2016 San Diego Comic-Con International, it was confirmed that real Kuchi Kopi nightlights were to be manufactured and available for purchase.
- Kuchi Kopi is voiced by H. Jon Benjamin in both Bob and Louise's fantasies, imitating a Japanese accent. It's very likely that Bob and Louise are remembering his voice from an audio/visual adaptation that they have both seen/heard.
- Louise has a small Kuchi Kopi purse in "In the Garden of Bob and Louise".
- Louise has a pair of Kuchi Kopi walkie-talkies, seen in "Slumber Party", "Two for Tina", "It Snakes a Village", and "Topsy".
- Louise introduces Kuchi Kopi to the class Chinchilla in "Adventures in Chinchilla-Sitting".