"MUTO" is an acronym for "Massive Unidentified Terrestrial Organism". Director Gareth Edwards stated that "it's basically the UFO of monsters". MUTOs are sexually dimorphic species. The female is much larger and walks on eight limbs - the male is much smaller, with one pair of his eight limbs modified into wings for powered flight. Though the MUTOs have an arthropod-like appearance. The angularity of the male MUTO's wing design was inspired by stealth aircraft As a side-effect of the radiation they absorb as food, the MUTOs are capable of causing electromagnetic interference, the male emitting EMP shockwaves from his claws and the female having an EMP field "Sphere of Influence" surrounding her instead.