Mothra (モスラ, Mosura?) is a kaiju, a type of fictional monster who first appeared in the serialized novel The Luminous Fairies and Mothra by Takehiko Fukunaga, Shinichiro Nakamura, and Yoshie Hotta. Since her film début in the 1961 film Mothra, she has appeared in several Toho tokusatsu films.
Generally regarded as female by English-speaking audiences, she is a giant lepidopteran with characteristics both of butterflies and of moths. She closely resembles an Inachis io, or a European Peacock Butterfly. The name "Mothra" is the suffixation of "-ra" (a common last syllable in kaiju names, viz. Hedo-ra, Ghido-ra, Ebi-ra, Goji-ra(Godzilla)) to "moth"; since the Japanese language does not have dental fricatives, it is approximated "Mosura" in Japanese. In the American dubbing of Mothra vs. Godzilla, Mothra is also referred to as: "The Thing". She is occasionally an ally to Godzilla but more often than not engaged in conflict due to his anger toward the human race. Mothra holds the most victories against the "King of Monsters." Mothra has never defeated Godzilla on her own, however. In each of these victories, Mothra had an ally; its own twin in Mothra vs Godzilla, Battra in Godzilla and Mothra: The Battle for Earth, and Mechagodzilla in Godzilla: Tokyo S.O.S..