This list of mythical creatures that begin with this letter and I am constantly gathering information from each continent, and is continually being updated.
Gremlin (Folklore)
A gremlin is a mischievous folkloric creature invented at the beginning of the 20th century to originally 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.
The original description of gremlins were that of tiny humans with elf-like ears and yellow eyes, wearing miniature overalls, and carrying tools sized for them yet somehow still eligible to be used as if they were the correct size. While depictions of these creatures vary, past findings present the animals to be similar to the chupacabra, with spiky backs, large strange eyes, and small clawed frames that feature sharp teeth.