گرملین

thumb|upright|A World War II gremlin-themed industrial safety poster A gremlin is a mischievous fictional creature invented at the beginning of the 20th century originally to explain malfunctions in aircraft, and later in other machinery, processes and their operators. Depictions of these creatures vary widely. Stories about them and references to them as the causes of especially inexplicable technical and mental problems of pilots were especially popular during and after World War II.