In the 65 years that he's been on screen, Godzilla has faced a multitude of different monsters. Sometimes are evil, while others act as benevolent protectors. Some stick around for a while, but most usually vanish forever after the credits roll.
Whatever the case, the Godzilla universe is home to some of the greatest giant monsters in all of science fiction. They've challenged the King of the Monsters time and time again, and while most aren't successful, some of them leave a lasting impression on the series.
Anguirus is Robbin to Godzilla's Batman. Always there when Godzilla needs him, he was a common sidekick in the Showa era. While he was first introduced as Godzilla's enemy, Anguirus seemed to patch things up with the big G and decided to fight on his side. With a back covered in sharp spikes, Anguirus is difficult to attack from behind, and Godzilla often bounces enemies off of it for added damage.
But while Anguirus may be a trusted ally, he's pretty useless by himself. Without any range attack, his ability to hold his own is limited, and if a monster ever manages to kick him onto his back, his belly is left exposed to potential damage. Still, despite enduring the most damage out of any of Godzilla's allies, he keeps coming back to help his buddy time and time again.
With a pair of curved blades for arms and a saw in his belly, Gigan is a mishmash of different monsters thrown together. Part machine and part animal, Gigan's body doesn't make a whole lot of sense. But Gigan is still considered one of the toughest foes of the 1970s.
Gigan is pretty much a giant Swiss Army Knife. He has a laser that he shoots out of his forehead, he can pull enemies into his spinning blade, and he can fly. Sadly, Gigan is one of the more arrogant monsters of the Godzilla universe, and it is here where he often meets his demise.
Another Swiss Army Monster, Megalon can seemingly do anything he wants. He can fly, and burro underground. He has a pair of spinning drills for arms. The thing that sticks out of his head shoots lightening bots. He looks like a cockroach from hell, and was sent from a group of underground humans to conquer the world.
But even with everything going for him, he still needs Gigan to help him fight off Godzilla and Jet Jaguar. And he still managed to loose. Much like Gigan before him, Megalon was simply not cunning enough to withstand Godzilla and his allies.
Part plant, part Godzilla, and part human, Biollante makes Audrey II look like a daisy. The result of a freak accident at a lab, Biollante begins life as a rose, before morphing into a freakish monster that takes root in Tokyo bay. Despite her ugliness, she's actually an ally to mankind, who's possessed by the spirit of a girl who died in a bombing.
Biollante's mouth is full of hundreds of razor sharp teeth, and she spits an acid that melts flesh. She also has an army of Venus Flytraps that can extend as long as she needs them. They can sprout out of the water and hold an enemy down, or pull them into her jaws. While Godzilla was too much for her to bear, the spirit that occupied her continues to live on.
6 Space Godzilla
Another creature born who is part Godzilla, Space Godzilla was created when some of Godzilla's skin sells were accidentally carried into space by Mothra. The result was a creature equal to Godzilla in almost every way, with the addition of psychic abilities that put him a cut above his earth born counterpart.
Space Godzilla can pick up and throw things with his mind, including Godzilla, and he was able to spawn crystal pits that give him power. He could also levitate and fly in order to get to where he needs to be. In the end, though, Godzilla and G-Force's Moguera unit made quick work of this Godzilla wannabe, and his potential was ultimately wasted.
5 Mecha King Ghidorah
A Frankenstein-like monster, combining pieces of the dead King Ghidorah with mechanical parts, Mecha King Ghidorah is the most advanced and powerful mech of the Heisei era. Created in the 23rd century, the cyborg was sent back almost three-hundred years in the past to prevent the destruction of Japan by Godzilla.
Combining advanced, almost otherworldly technology with Ghidorah's size and strength, Mecha King Ghidorah was the best of both worlds. In addition to firepower from three heads and powerful grapples that were strong enough to restrain anything, Mecha King Ghidorah could have been the death of Godzilla himself. And while he was defeated, his mechanical remains were used by G-Force to build Mechagodzilla.
Created by the oxegen destroyer that killed the first Godzilla in 1954, Destoroyah is the grim reaper of the Godzilla series. Appearing around the same time that Godzilla was dying, Destoroyah threatened to end the human race with his army of crab-like minions. And with Godzilla's death threatening to cause the apocalypse, Destoroyah's spawn could've replaced the human race as earth's dominate species.
Able to break himself down into smaller versions of himself, Destoroyah is a threat on every level. His arsenal of attacks includes a horn that could turn into a katana, able to slice through anything and everything. Not even Godzilla could kill Destoroyah, and he defeated, it was a hollow victory.
There have been three incarnations of Godzilla's robotic doppelganger in the live action Toho films. The first from 1974 was built by space aliens to take over the world. The second was created by G-Force using the remains of Mecha King Ghidorah. And the third, sometimes called Kiryu, was brought to life using DNA from the 1954 Godzilla.
But no matter who built him, Mechagodzilla has remained one of Godzilla's most formidable foes. Possessing state of the art weaponry like missiles, lasers, and jetpacks, Mechagodzilla has everything he needs to tame his adversaries. While Godzilla usually beats him in the end, there have been more than a few times when Mechagodzilla has come close to toppling the King of the Monsters for good.
2 King Ghidorah
Godzilla's arch nemesis, Ghidorah is the Joker of the Godzilla universe. A three headed dragon of otherworldly origins, Ghidorah appears and re-appears regularly to give Godzilla a good thrashing. Perhaps the biggest of the Godzilla kaijus, he towers over all those who oppose him.
His wings generate hurricane-force winds, his serpentine necks can asphyxiate his victims like a boa, and each head shoots yellow lightening. But it's the sound he makes that stands out the most, a telltale laugh that makes it seem as though he's mocking his opponents.
While not indestructible, Mothra is easily the smartest and most cunning creature in the Godzilla universe. Possessing human-like emotion and empathy, she's able to easily outsmart her attackers, exploiting gaps in their judgement to bring down even her toughest adversary.
Mothra's greatest asset of all is her sense of duty. Sent to protect the earth from potential harm, Mothra is willing to do whatever it takes to complete her mission, even if that means sacrificing her life, a feat that most monsters are unwilling or unable to do. And while she may not live to see another fight, her legacy lives on in her offspring, who go on to take her place.