Gremlins

Struggling inventor Randall Peltzer visits a Chinatown antique store to find a Christmas present for his son, Billy. In it, Randall uncovers a small and furry creature called a mogwai (Cantonese: 魔怪, 'devil'). The owner, Mr. Wing, refuses to sell it to Randall, but his grandson secretly does, warning Randall to remember three important rules concerning its care – keep the creature away from light, especially sunlight, which will kill it; do not let it come in contact with water; and above all, never let it eat after midnight.
In Randall's hometown of Kingston Falls, Billy works at the local bank, but fears that his dog Barney will be put down by widowed miser Ruby Deagle. His father returns and offers him the mogwai, now named "Gizmo", as a pet and informs him of the rules. Gizmo is friendly and docile, but when Billy's friend, Pete Fountaine, accidentally spills water on Gizmo, five more mogwai spawn from him – a more mischievous sort led by the aggressive Stripe, named after the white and mohawk-like tuft of fur on his head. Billy shows one of the mogwai to his former elementary school science teacher, Roy Hanson, spawning another mogwai, whom the latter experiments on. Back home, Stripe and his fellow mogwai trick Billy into feeding them after midnight by sabotaging his bedside clock. They form cocoons, as does Hanson's mogwai, which soon hatch, emerging as destructive and reptilian imp-like monsters called "gremlins". Hanson is murdered by his gremlin, while those at the Peltzer house torture Gizmo and assault Billy's mother, Lynn.
Lynn and Billy are able to dispatch all the gremlins sans Stripe, who escapes to the local YMCA where he jumps into its swimming pool, spawning an army of gremlins that wreak havoc on Kingston Falls. Many locals are injured or outright killed during their rampage, including Deagle. The police are helpless in the ordeal, as they too fall victim to the gremlins' mischief. After Billy rescues his co-worker and girlfriend, Kate Beringer, when the gremlins attack the bar she works at, and they seek refuge in the bank, the latter discloses that her father went missing on Christmas Eve when she was nine years old, but was then found dead in their house's chimney several days later. Planning to surprise his family while portraying Santa Claus, he inadvertently slipped and broke his neck while climbing down the chimney. Still suffering from post-traumatic stress disorder due to the incident, Kate confesses how this led to her dislike of the holidays.
The trio find the gremlins gathered in the local movie theater due to morning approaching and set off a natural gas explosion, killing them all except for Stripe, who left the theater earlier to retrieve candy at a Montgomery Ward store across the street. They follow Stripe into the store, where he attempts to use a fountain to spawn more gremlins, but Gizmo then opens a nearby skylight, exposing Stripe to sunlight and killing him.
As the local news reports on the incident, Mr. Wing arrives at the Peltzer house to reclaim Gizmo. He scolds the family for their negligence and criticizes Western society for its carelessness with nature. However, as he turns to leave, Gizmo, having bonded with Billy, bids him goodbye. A compassionate Wing then concedes that Billy may be ready to properly care for him one day.