Grant Grant is one of the main characters of the horror-comedy film Slither. He is the husband of film protagonist Starla and becomes the film's antagonist when he becomes the host for a parasitic alien life-form. He is portrayed by Michael Rooker.
One night, Grant becomes frustrated when his wife Starla isn't in the mood for intimacy. He goes out to a bar where he meets his old high-school sweetheart Brenda Gutierrez, and as the two reminisce and enjoy each other's company, they go out to an open field away from prying eyes. Grant notices something in the tall grass and discovers a large, maggot-like creature. The creature extends some kind of stinger which shoots into Grant's chest. The alien needle is a parasite and it burrows through Grant's body and into his brain, fusing with him and taking control.
As time passes, Grant follows the nature of the parasite, buying large amounts of meat and secretly killing neighbourhood pets, cattle and wild animals. He also visits Brenda at her home and rapes her, using his new mutant proboscis to turn her into a breeder. He then locks Brenda away in a barn out in the woods where he feeds her the raw meat he's been gathering. As time goes on, Grant becomes steadily less human, developing growths and lesions all over his body. Eventually, Starla catches on to his strange behaviour and witnesses his new mutant appendages protruding from his torso. Grant then flees into the woods.
Three days later, animals continue disappearing from the farms around Wheelsy and police chief Bill Pardy and Mayor Jack MacReady round up a posse to find Grant and the missing Brenda. During a stake-out, they find Grant out in a field dragging a cow into the woods. By this point, Grant no longer looks human, having turned into an amorphous blob of a creature with tentacles. The posse follow the mutant Grant into the woods and come across the barn where Brenda has been held. They go inside to find Brenda who has swollen to grotesque proportions as her body expands with thousands of small parasitic slugs. Shortly after, Brenda is torn apart from the inside as her enormous clutch breaks free, swarming over the posse members and slithering towards town where they go about infecting the population. Bill, Starla and MacReady avoid being infected as they keep their mouths shut to keep the slugs from entering.
Meanwhile, Grant returns home where he makes his "nest". Guiding the worm hosts telepathically as extensions of himself, he sets about infecting and/or consuming all life in town, adding multiple human bodies to his own biomass and growing like a sentient cancer, intent on growing and spreading until he covers the entire world.
Starla is captured by Grant's zombified slaves and brought home where Grant attempts to "set the mood" before making her a part of him. In a sense, Grant is still being governed by his emotions, most notably his love for Starla. Starla notices this and attempts to use it to her advantage, keeping Grant distracted while Bill Pardy and Kylie Strutemyer attempt to get close enough to kill him. With his multiple slaves acting as his eyes and ears, Grant notices what's happening. Bill tries to throw a grenade at Grant, but Grant slaps the grenade away with a tentacle and it explodes in his swimming pool. Grant then grabs Bill and attempts to turn him into a breeder, jabbing one of his proboscis tentacles into Bill's torso. Bill manages to grab the second proboscis and forces it into the ruptured nozzle of a propane tank. The volatile gas enters Grant's swollen body and Starla grabs Bill's gun, shooting a bloated area of Grant where the gas is collecting. The gunshot ignites the gas and Grant explodes in a shower of mutated meat. When Grant dies, all of the worms and infected townsfolk die as well.