- "That dog looks peaceful sleeping, but if I get too close...Cujo!"
- —Max on Pompidou
Pompidou was a dog used in illegal dog fights that Frank once participated in. When Frank had a change heart regarding the safety and treatment of the dogs, he saved them. Pompidou was among the dogs he saved. Frank decided to adopt Pompidou as his own and used him as his guard dog. When Rachel Amber became romantically involved with Frank Bowers, she was the only other person Pompidou showed any kind of affection to. 
She notes that he looked peaceful, but could attack her like Stephen King's Cujo if she wasn't careful. At the end of the day, Pompidou is outside the RV barking at the snowfall when Frank steps outside the RV to shout at him for barking before noticing the snow himself.
When Max arrives at the Two Whales Diner, the dog is sitting outside with Frank, who is asleep. When Max attempts to approach Frank and his dog, the dog chases her off when he starts to bark. Frank wakes up long enough to tell his dog to stop barking before returning to sleep.
Later, Frank's dog accompanies Frank to the beach to watch the eclipse that occurs at the end of the day.
When Max Chloe Price attempt to break into Frank's RV, Pompidou was on the other side of the door, growling at their proximity. While Chloe searched through a nearby garbage can for something to use as a direction, Max entered the Two Whales Diner to retrieve Frank's keys. Speaking with officer Berry, she learned about Pompidou's history a dog used in dog fights before he was rescued by Frank. Berry believed that Frank raised Pompidou on and how to attack trespassers for "blood".
When Max approaches Frank for his keys, she tries to use the information she learned about Pompidou from Berry. Frank asks where she learned about the dogs. Max complements his actions, calling him "animal lover". She tries to use his relationship with the dog to get him to give her his keys, asking if she could pet Pompidou.
Frank tells her that he wouldn't even allow her pick up the dog's shit and knew what she really wanted was his keys. He sets them on the table, giving her the opportunity to grab them off the time. When she rewinds, she leaves the diner and heads back to the RV. Chloe unlocks the door after giving Max a bone from the trash. When she opens the door, Pompidou runs out toward her.
Max throws the bone across the parking lot. Pompidou follows after it and settles down where it landed to play with it. Chloe declares that they made the dog "their bitch" before entering the RV. Max assumes that the dog would preoccupied for a time, but would likely return if they weren't quick. After they finish investigating Frank's RV, Chloe pulls out of the parking lot in her truck. Pompidou barks after them, drawing Frank's attention to the diner's window as Chloe pulls out of the parking lot.
Max throws the bone toward the road. Pompidou runs after it without hesitation, but doesn't see the truck coming toward him. Max hears the truck hit the break and fears the worst has happened to the dog. Chloe assures her that Pompidou has likely not been hurt and that they had to hurry and investigate before Frank came out.
When Max and Chloe confront Frank at his RV, Pompidou is inside.
Pompidou waits inside the RV. If Frank gets in a fight, Pompidou comes out and assists him. If Chloe has a gun during this confrontation, both Pompidou and Frank end up dead. If not, Pompidou bites Chloe in the leg, prompting Max to rewind to before the fight.
Frank states that Pompidou is "lucky to be alive." Pompidou's injuries prevent him from assisting Frank in any altercation.