Gremlins (folklore)

A Gremlin is a mythological creature similiar to a fairy or goblin which had their origins during the World Wars, in which they were said to cause havoc on aircraft - a trait which they have been continually given since their creation, though in time their destructive nature has come to include almost any type of technology.

They have become a staple of fiction and inspired many mischievious and/or malicious beings throughout the ages - the most famous of which are arguably the titular monsters of the comedy-horror "Gremlins" (though these monsters bared little in common with the folkloric creatures).

Although not popularly used until after WWII the myth of the Gremlin seems to be older, the earliest example going back to the 1920s - it may of been a way for airmen to explain faults in aircraft or malfunctions, which were often seen as inexplicable and over time they became a part of the public imagination.