Plot
A meteorite brings a malevolent, sentient extraterrestrial parasite to Earth. The parasite enters the town of Wheelsy, South Carolina, where it infects wealthy resident Grant by taking over his body and absorbing his mind. With the alien in control of him, Grant begins to transform into a grotesque, tentacled monstrosity. He also abducts and infects a local woman, Brenda, to serve as a breeder for his alien larvae. His wife Starla learns that he hasn't been to the doctor's in over a year and she becomes suspicious over the changes in his appearance and behavior, leading to Grant attacking her. When the police arrive to rescue Starla, Grant flees.
During their search for Grant, a posse led by police chief Bill Pardy discovers Brenda, whose body has become inhumanly bloated from the larvae growing inside her. The slug-like larvae burst from her body and infect everyone in town except Starla, Bill, Mayor Jack MacReady, and teenager Kylie Strutemyer (Starla, Bill and Jack realised that they could escape infection by covering their mouths and Kylie was able to pull the larvae out of her mouth before it could get too deeply inside). Those infected by the larvae become part of a hive mind controlled by Grant, who intends to consume all lifeforms until only his consciousness remains. However, Grant also retains his love for his wife and seeks to be reunited with her. Thanks to Kylie having glimpsed the hive mind before she was able to pull out her own larvae, the survivors deduce that killing Grant will eliminate the rest of the aliens before they are attacked by the infected townspeople. Bill and Kylie escape, but Starla and Jack are captured.
Armed with a grenade to kill the monster, Bill and Kylie head to Grant's home, where the infected are being absorbed by the increasingly mutated Grant. Jack and others are turned into breeders for more larvae, while Grant keeps Starla uninfected in the hope of regaining her love. After waking up, Starla arms herself with a sharp brush and goes downstairs to find Grant. She tricks him into believing she still loves him and stabs him with the brush. Grant becomes angry and throws her across the room. Bill and Kylie enter the house after shooting several alien townfolk, and euthanize an infected Jack after he begs for death. Bill tries to use the grenade, but Grant knocks it into the pool, then subdues Kylie with a couch and attempts to infect Bill with his tentacles. While one of the tentacles stabs Bill in the stomach, Bill attaches the other tentacle to a propane tank. Starla shoots Grant who, filled with flammable gas, explodes, killing the rest of the aliens and saving Bill. With everyone else in Wheelsy dead, the three survivors head off to seek help.
In a post-credits scene, a cat approaches Grant's remains and becomes infected by the alien parasite.
