|Appearance||Day of the Dead|
Bub was apparently in one branch of the United States Military before the Zombie outbreak, possibly the US Army or Marine Infantry seeing as he recognizes ranks and can handle firearms with ease. When the undead apocalypse occurred, Bub died and reanimated. He was one of the zombie specimens captured by the Seminole Storage Facility from the zombie-infested caves.
Rather than dissect Bub like the other zombie specimens, Logan instead tried to successfully domesticate him. He demonstrated this to Sarah and Rhodes by giving Bub several objects which the latter recognized from when he was alive, and remembered .
Eventually, Logan rewards Bub by feeding him the fresh remains of Miller and Johnson. Later, Bub is able to figure out how to removed his chain and discovered Logan dead in the freezer where he eagerly tried to show the slain man that he removed the chain only to realize he has been killed. Enraged at his mentor's death, Bub acquired a discarded gun and went on a hunt for Rhodes in the complex, attacking Steel before meeting his final objective.
Bub stalked Rhodes through the complex, shooting him several times, until Rhodes bumped into a horde of zombies.
Initially, Bub had the typical mentality of any other rabid zombie;however thanks to Logan's training and reeducation, Bub has regained some human intelligence. Logan concluded that Bub was able to unlock his memories from before his death and transformation into a zombie, as seen when Bub recalled how to use a razor to shave his face despite Logan never showing razors to Bub before. His intelligence continued to develop;Bub was able to speak a mumbled sentence, and his intellect even allowed him to operate and use a pistol. Later he would escape his chains by loosening an exposed screw, and accurately concluded that Rhodes was responsible for Logan's murder.
Bub's relationship with Logan improved to the point where he identified him as a friend instead as food; he made no attempt to attack Logan and trusted him entirely. Bub was still hostile to other humans however, and attempted to shoot Rhodes with an empty pistol. After discovering that Rhodes murdered Logan; Bub was distraught, crying, and sought revenge against Rhodes. Finally, as Bub watched other zombies devour Rhodes, he taunted the captain with a military salute instead of joining the other zombies in their feast.
- Bub is the third zombie in the series seen carrying a gun; The first was the zombie who took Roger DiMarco's assault rifle, and the second was the undead Stephen Andrews.
- Bub is also the first zombie in the series seen aiming and firing a gun.
- Much like Big Daddy, Bub is never seen attacking a living human for food, and thus only kills the main human antagonist as an act of revenge. Bub did, however, consume the butcherd flesh and organs of the recently deceased Pvt. Johnson and Pvt. Miller given to him by Dr. Logan, implying he has not entirely lost his taste for human flesh.
- Dr. Logan stated that he named Bub after the former's father.