Gremlins:
An inventor gives his son an odd little creature which multiplies into monsters which wreck the town.

Gremlins 2 - The New Batch:
Billy Peltzer and Kate Beringer move to New York City and meet up with their Mogwai friend, Gizmo, when a series of accidents creates a new generation of diverse gremlins. Billy, Kate, and Gizmo must once again use all their experience to prevent another catastrophe.