Don't Kill It (2016)

While chasing deer on a hunting trip in southern Mississippi, Gabriel's dog discovers and opens a small, unusual golden container. When Gabriel finds his dog, it acts strangely before violently attacking him. After shooting and killing the dog in self-defense, Gabriel returns home, displaying the same unusual behaviors and black eyes. In the wake of killing his family, Gabriel enters a neighboring house and begins to slaughter everyone in sight before being shot dead by his neighbor, Marcus, who immediately gets the same black eyes and completes Gabriel's task, by murdering his own family.

A few days later, demon hunter Jebediah Woodley hears of the murders on the radio and travels to the small town to investigate. At the same time, FBI agent Evelyn Pierce, who grew up in the area, has been assigned to investigate the case for possible links to domestic terrorism. Woodley travels to the local police station to express his concerns. However, Pierce - along with Dunham, the local police chief - quickly dismiss Woodley's claims of demon activity and order him to be detained under the assumption that he is mentally ill. Whilst Pierce leaves to interview a witness to the most recent series of murders, Woodley advises her to ask about the killer's eyes. Upon interviewing the witness, it is explained to Pierce that Gabriel entered the witness' home and killed her daughter before being shot by her husband, Marcus. Marcus then executed their son and attempted to murder her before she escaped. Pierce learns that the husband's eyes also turned black before he went into a murderous rampage, and thus realizes Woodley is in fact telling the truth.

Back at the station, Woodley is released by Pierce and Dunham. At a nearby café, Woodley explains to them that the demon possesses the body of whoever killed its last host. He goes on to say that the only way to defeat the demon is by killing the host whilst simultaneously ensuring one's own death; his own father captured the demon when he was a child and poisoned himself before killing the host. Woodley held onto the captured demon for decades before it escaped.

After stocking up on weapons and ammunition, Woodley and Pierce's investigation takes them to a nearby cabin in the woods. Woodley and Pierce mistakenly capture a drunkard living in the cabin, who says he shot the demon in the stomach and that it was his friend, Glen, that executed the demon's host and ran off into the woods immediately following the incident. Woodley and Pierce proceed to track the demon through the woods, which ends with Pierce being attacked by the demon. Instead of killing her, the demon shows an interest in Pierce and attempts to get her to kill it, giving her horrible visions of an apocalyptic future. Woodley tries to subdue the demon, but before he can do so, it manages to escape. Later, Pierce visits her old home with Woodley and tells him that she drowned to death in her garden pool as a child, but was mysteriously brought back to life. This resulted in her family being persecuted and run out of town by superstitious citizens.

Dunham organizes a town hall meeting, late at night, to warn citizens of the danger. During his speech, Dunham is interrupted by the demon, who slaughters the congregation and rapidly changes bodies before Woodley can get to it. It flees to a nearby house, where it manipulates a young girl into killing its host, thus taking over the girl. Dunham flees the town; at the same time Woodley enters a church, where the local pastor, Erikson, who remains suspicious of him, accuses Woodley and Pierce of being evil and the cause of mayhem. Woodley reacts by punching Erikson, and leaves to rejoin Pierce.

The father of the now-possessed girl, Emmett, encounters Woodley and Pierce in the middle of the anarchy, urging both to help him. Woodley and Pierce travel to Emmett's home, where it is revealed Emmett has locked his daughter in a backroom. Woodley convinces Emmett to poison himself and kill his daughter, ending the demon's trail as before. However, the FBI - who have been called there secretly by Pierce - storm the home before Emmett can carry out the killing, and Emmett dies uselessly; the head agent, Deacon Shepherd, has Woodley arrested for poisoning him. The possessed girl slaughters the FBI agents except for Shepherd, who mortally wounds the demon before it flees.

Fleeing farther into the woods, the demon's host eventually dies and it possesses Shepherd, given he mortally wounded the demon minutes prior. The demon once more goads Pierce into killing it. Woodley risks his own life to successfully capture the demon and prepares to poison himself in an effort to kill the demon, like his father before him. Before completing the ritual, Woodley and Pierce are interrupted by Erikson, who has tracked them down with an angry mob of congregation members under the assumption Woodley is evil and has captured an innocent man. Erikson attacks Woodley as the mob frees Shepherd, who immediately begins to murder everyone present. Erikson kills Shepherd and is possessed. As the demon tries to kill Woodley, Pierce grabs a vest covered in grenades from a dead FBI agent's corpse and pulls the pin out before killing Erikson. As the demon takes over Pierce, apocalyptic phenomena from Pierce's earlier visions begin to occur. Whilst possessed Pierce levitates off the ground, but the grenade in her hand detonates, killing both her and the demon.

Some time later, Woodley is seen on a boat in the middle of the ocean. Having captured the remains of the demon in a flask, Woodley drops the flask into the ocean. The flask is quickly consumed by a great white shark, implying the events will repeat in the near future.