Buttercup is a "hideous-looking cat" that belonged to Primrose Everdeen. Prim named him Buttercup because she insisted that his muddy yellow coat matched the bright flower. He hates Katniss due to her attempt to drown him in a bucket, though they sometimes act somewhat friendly to each other. After Katniss starts to feed him the entrails from her hunting kills, he stops hissing at her. Buttercup is said to be a good mouser and even catches the occasional rat.
Buttercup often sleeps with Prim and watches the area at night. He hisses at the sight of Katniss unless she feeds him.
The cat moves to Victors' Village with his family after Katniss won the 74th Hunger Games, but dislikes their new house and often returns to their old home in the Seam. Once Katniss finds him in her old home, she tells him he is an ugly cat which he replies by nudging her so he could be petted. Katniss feeds him some of her kill and rubs in between his ears. The two bond together with this and their dislike of their new home. Katniss scoops him up into her arms and leaves the old home. When she lets him go, Buttercup runs away and hides under a bush. He eventually gets used to his new life and starts to sleep with Prim again. Prim cares for him and does not seem to leave him. Buttercup comforts her once again when Katniss is reaped in the third Quarter Quell.
Buttercup also appears in the final installment of the series, Mockingjay. When Katniss returns to the destroyed District 12, she goes to the remains of her house and finds Buttercup there, as opposed to Prim's goat, Lady. Katniss figures, sarcastically, that Buttercup had to live, not Lady, because Lady actually served a purpose in the household. Katniss also finds her family's plant book, one of Prim's ribbons, a picture of her parents on their wedding day, and her father's hunting jacket in Katniss' house in Victors' Village. It's unknown how Buttercup managed to survive in the destroyed District 12.
Buttercup and Katniss play a game of Crazy Cat, where Katniss uses a flashlight to shine a light on the walls and the floor and Buttercup tries to catch it. The citizens of District 13 enjoy this simple game very much, which reveals the lack of entertainment in their day-to-day lives. It is mentioned by Katniss that Buttercup's reactions to the light are similar to what her own reactions would be if the light represented Peeta. Buttercup becomes crazy if she leaves the light shining in place where he can't reach it (she is upset and very distraught over Peeta's torture and imprisonment by the Capitol), and if she turns the light off, Buttercup is confused and upset for while, but eventually gets over it. She realizes that that's what would happen to her in in fact the light were Peeta and she was Buttercup. That realization makes her go into a depression.
Buttercup is stuffed into Katniss' hunting bag, and Prim cries when she sees him. One of Katniss' demands is that, if she becomes the Mockingjay for the rebels, Prim will be able to keep Buttercup. This request is accepted, so Katniss and her family were moved to a room were there were a window that Buttercup could use to go outside for a few hours of the day.
Buttercup almost causes the death of Prim in Mockingjay. She is looking for him, and word has spread that there will be a bombing shortly in District 13, as Peeta subtly slipped it into a broadcast interview. Katniss realized that Prim is missing, and assumes that it must be because of the cat. Prim makes it back with Gale and Buttercup just before the doors to the bunker are closed.
Buttercup lived in the bowels of District 13 with Mrs. Everdeen, Katniss, and Prim. He slept next to Prim in her lower bunk. Katniss holds him by the neck since he almost killed Prim but she lets go after Prim asks her to. The two sleep together during the night in the bunker. Katniss plays with him during the night with a flashlight, and pretends to be him to imagine how to get Peeta back.
After Prim's death, Katniss returns once more to District 12. Buttercup travels all the way from District 13 to District 12 to find Prim. She finds Buttercup, and is enraged. He looks at her, in hope for Prim, and she screams furiously that Prim is dead, and that he should leave. He does not, and they mourn Prim together, until she comes to accept him. When Katniss slept that night, instead of Buttercup protecting Prim from the night, Buttercup protects Katniss, watching for any intruders, because Prim loved her older sister and she and Buttercup are both upset over her death.
Together, Katniss and Buttercup mourn and cry about their lost loved one. Katniss cries into his fur and he rests his head on her. They both start get along because they only have each other. Katniss has Peeta, but he doesn't know Prim as well as Katniss and Buttercup.
Buttercup was described as a hideous-looking cat. He had a mashed-in nose, half of one ear missing, and eyes the color of a rotting squash and a muddy yellow coat. Despite Buttercup being presumed to be the tuxedo cat in The Hunger Games film, he has been shown to be ginger, as described in the books, in The Hunger Games: Catching Fire. https://twitter.com/QuarterQuellOrg/status/389516132975394817/photo/1
Prim had a strong relationship with Buttercup. Prim found and healed him and later she tried to stop Katniss from drowning him and kept him as a pet. Buttercup would always sleep with Prim and he would always watch over her during the night to make sure she would stay safe. In Catching Fire, though he did not like the new house he lives in with the Everdeens in the Victor Village, he would often leave but always come back for Prim.
In Mockingjay, the two were glad to be able to be with each other after Katniss made a request to keep Buttercup for Prim's sake. He continued to protect her over the night and slept by her. Prim was willing to be killed for Buttercup after she almost died during the bombing of District 13 by the Capitol. Prim realized he was still in her room and went there to retreieve him so he wouldn't be killed but both of them would have died if not for Gale. Buttercup traveled all the way from District 13 to 12 just to find Prim but was sad when he did not find her.
- "I'll still cook you."
- ―Katniss Everdeen to Buttercup[src]
Katniss and Buttercup did not like each other at first. Katniss saw Buttercup simply as another mouth to feed so she tried to "drown" him in a bucket full of water when Prim stops her. After that, Buttercup would always hiss and attack her whenever he saw or came near her. He would only stop hissing when he was fed, with the entrails of Katniss' kills.
In Catching Fire, Katniss and Buttercup both disliked the new house at the Victor's Village and often visited the old house at the Seam. Katniss saw he was there and rubbed his stomach, she says that is the first time the two ever bonded together.
In Mockingjay, Katniss brings him with her to District 13 for Prim's sake after she finds him at their destroyed house at the seam. Although Katniss stuffed him in a hunting bag and hit him on the stairs, which cause him to hiss and try to escape, Katniss made a request for Buttercup to stay with them and be able to go outside for a while and he could stay with Prim. After the bombing, Katniss held a grudge toward him after he almost killed Prim by her returning to their compartment to retreive him and take him to safety during the bombing. Buttercup traveled all the way from District 13 to 12 just to find Prim but was sad when he did not find her. Katniss yells at him "She's dead!" and the two mourn together, for Prim.
In The Hunger Games film, Buttercup is shown as a fuzzy black and white tuxedo cat as opposed to the scraggly yellow tabby portrayed in the books, however in The Hunger Games: Catching Fire, Buttercup was recast as a fluffy ginger cat.