King Ghidorah (キングギドラ Kingu Gidora?) is a three-headed dragon kaiju created by Toho that first faced Godzilla in the 1964 Godzilla film, Ghidorah, the Three-Headed Monster.
Widely considered to be Godzilla's arch-nemesis, King Ghidorah made his debut in Ghidorah, the Three-Headed Monster, where he arrived on Earth inside a meteor and prepared to destroy it just as he had done to Venus thousands of years in the past. He was driven off by the combined might of Godzilla, Rodan and Mothra, but returned in Invasion of Astro-Monster as a pawn of the Xiliens in their invasion of Earth. King Ghidorah was unleashed on Earth once again by the Xiliens, along with Godzilla and Rodan, now under the invaders' control as well, but a group of humans managed to sever the aliens' hold on the monsters. Godzilla and Rodan teamed up against King Ghidorah again, sending him back into the void of space. In Godzilla vs. Gigan, King Ghidorah was now under the control of the M Space Hunter Nebula Aliens, who deployed him alongside the cyborg monster Gigan to assault the Earth. Once again, King Ghidorah was beaten by Godzilla, this time aided by Anguirus, and retreated back into space with Gigan. In Zone Fighter, King Ghidorah was one of the Garogas' Terror-Beasts, and did battle with Zone Fighter twice, managing to escape with his life. In the chronologically final film of the Showa series, Destroy All Monsters, King Ghidorah was unleashed by the Kilaaks in a desperate final attempt to defend their base of operations from Godzilla and the Earth monsters, only to be killed in battle by their combined might.
Toho brought King Ghidorah back for the Heisei series in Godzilla vs. King Ghidorah, where he was now the pawn of time-traveling terrorists and the result of three genetically engineered creatures called Dorats being fused together by a hydrogen bomb explosion. The Futurians unleashed King Ghidorah in Japan, demanding for the nation's surrender, but their plot was interrupted when Godzilla appeared and battled King Ghidorah. After destroying the Futurians' time machine, Godzilla decapitated King Ghidorah's middle head and shredded his wings, leaving the creature comatose in the ocean. A defector from the Futurians, Emmy Kano, managed to salvage King Ghidorah's remains in the future and revive him as the cybernetic Mecha-King Ghidorah, then brought him back to the present to battle Godzilla. King Ghidorah was later featured as the antagonist in Rebirth of Mothra III, where he was once again a malevolent space monster, this time seeking to feed on the life forces of human children. King Ghidorah fought and nearly killed Mothra Leo, who traveled back to the Cretaceous in an attempt to destroy King Ghidorah while he was younger and weaker. After seemingly killing Cretaceous King Ghidorah, Leo returned to the present only to find King Ghidorah still alive and well. Leo then transformed into his most powerful form, Armor Mothra, and finally destroyed King Ghidorah.
King Ghidorah's only appearance in the Millennium series came in Godzilla, Mothra and King Ghidorah: Giant Monsters All-Out Attack, where he was one of the three Guardian Monsters that fought to defend Japan from Godzilla, alongside Baragon and Mothra. King Ghidorah was teased through a cave painting in the second film in the MonsterVerse, Kong: Skull Island, and is set to appear in Godzilla: King of the Monsters, the sequel to Legendary Pictures' Godzilla.
It made an appearance in the New York racetrack as one of the Stage Hazards.