Gremlins

Randall Peltzer, a struggling inventor, visits a Chinatown antique store in the hope of finding a Christmas present for his son Billy. In the store, Randall encounters a small, furry creature called a mogwai (Cantonese: 魔怪, "monster"). The owner, Mr. Wing, refuses to sell the creature to Randall. However, his grandson secretly sells the mogwai to Randall, warning him to remember three important rules that must never be broken – do not expose the mogwai to bright lights or sunlight which will kill it, do not let it get wet, and never feed it after midnight.