Anatomically correct gremlin

Question

This is not about the cute Holywood variety of gremlins by Joe Dante. I am interested in the one that Wikipedia describes thus:

A gremlin is a folkloric mischievous creature that causes malfunctions in aircraft or other machinery. Depictions of these creatures vary. Often they are described or depicted as animals with spiky backs, large strange eyes, and small clawed frames that feature sharp teeth.

The real requirement here is an animal that, for whatever reasons, attacks airliners in mid-flight. The creature is likely able to match aircraft in flight ceiling and speed.

Evolutionary pressures leading to this and the creature's motivation (food, territory defense maybe?) are not required, but would be nice to have.

Answer 1

Gremlins hate to fly.

Gremlins are land creatures and residents of machines. They are subtle fairies related to leprechauns, brownies and others of that ilk, but the gremlins are a population that has been differentiating from their more widespread predecessors since the industrial revolution. On land they can cause some issues but are generally benign inhabitants, and can sometimes even help maintain the machines they live in, cleaning dirty gears, roughing up slippery old belts, removing detritus and so on. This accounts for certain ancient machines that somehow have survived to the modern age while still fulfilling their function.

Gremlins are descended from Knockers and were originally creatures of the deep earth and mines. They are ok on the surface inside the dark metal of machines. But flying scares them. The planes are otherwise great places for them to live. Gremlins that find themselves at altitude will take measures to encourage the pilots to land the plane.

Answer 2

First, it is strange for Galactus Renan to ask the kind of question that is usually the icewar who asks.

A gremlin can be a type of gecko, related to the Thorny devil. Like all other cold-blooded animals, they become more active with the heat, so the heat emission from the machines seems like an interesting niche to inhabit and due their small size they pass unnoticed.

The problem is when the aircraft engines are in operation, emitting a lot of heat and the gremlins feel an absurd difference in atmospheric pressure, they become aggressive. Something about their metabolism changes greatly, as does the appearance of a bloobfish at different pressure gradients.