Produced by Grantray-Lawrence Animation, headed by Grant Simmons, Ray Patterson and Robert Lawrence, it was an umbrella series of five segments, each approximately seven minutes long, broadcast on local television stations that aired the show at different times. The series ran initially as a half-hour program made up of three seven-minute segments of a single superhero, separated by a short description of one of the other four heroes. It has also been broadcast as a mixture of various heroes in a half-hour timeslot, and as individual segments as filler or within a children's TV program.
The segments, and their original rotations, were:
Sixty-five episodes of three seven-minute segments were produced, for a total of 195 segments that ran initially in broadcast syndication from September 1, 1966 to December 1, 1966. The series, produced in color, had extremely limited animation produced by xerography, consisting of photocopied images taken directly from the comics and manipulated to minimize the need for animation production. The cartoons were presented as a series of static comic-strip panel images; generally the only movement involved the lips, when a character spoke, the occasional arm or leg, or a fully animated black silhouette. The series used the original stories largely in their entirety, showcasing Jack Kirby, Steve Ditko and Don Heck art, among others, from the period fans and historians call the Silver Age of comic books.
Stan Lee, Marvel's editor and art director at the time, said in 2004 that he believed publisher Martin Goodman negotiated the deal with Grantray-Lawrence and that Lawrence chose the characters to be used. Lawrence rented Lee and his wife apenthouse apartment at 30 East 60th Street, near Madison Avenue, for Lee's use while he worked on the series. (Lee lived in Hewlett Harbor, New York, on Long Island, at the time.) Lee recalled, "I really don't remember any reaction from the Marvel artists involved. I wish I could claim to have written the [theme song] lyrics, because I think they're brilliant, but alas, I didn't". In the meantime, Grantray-Lawrence subcontracted production of The Mighty Thor segments to Paramount Cartoon Studios (the animation division of Paramount Pictures, formerly known as Famous Studios), headed at that time by Fleischer Studios veteran Shamus Culhane.
Marvel announced the series in the "Marvel Bullpen Bulletins" of the November 1966 issues, stating in that monthly fan page's hyperbolic style that, "It won't be long before our swingin' super-heroes [sic] make their star-studded debut on TV, appearing five nights a week — that's right, five — count 'em — five nights a week, for a half-hour each night. So you've just got time to make sure your set's in good working order — check your local paper for time and station — and prepare to have a ball!"
The Lava Men are a race of Subterraneans who were mutated by the demon Cha'sa'dra, a native of Limbo, into a lava-skinned form. The first Lava Man to visit the surface world was Jinku, who was propelled to the surface by a volcanic reaction triggered by the trickster god Loki. This Lava Man fought Thor before he was returned underground. Later he and other Lava Men later fought Thor's teammates, the Avengers. Cha'sa'dra was among the demons of Limbo who appeared on Earth during the "Inferno" storyline, and when he was destroyed in combat with the Avengers, the Lava Men were apparently transformed into solid, non-living matter.
Lava Men had red skin of rock-hard consistency. A Lava Man's body has twice the density of a normal human being's. Upon death a normal Lava Man immediately decomposes into dust. A small number of Lava Men have undergone a metamorphosis giving them golden skins. Grotesk has rendered all Lava Men mute under his rule. No clearly female Lava Men have been depicted to date.
Less than one thousand Lava Men are known to exist. The Lava Men formerly had a tribal government, but became a monarchy ruled by Grotesk, although the golden Lava Men remained under tribal rule. Their technology level is primitive and the Lava Men are deeply religious, and peaceful except when stirred to war by religious fervor. Lava Men were formerly nomadic. Though not a Lava Man himself, Grotesk ruled the red Lava Men. Jinku was a shaman of the gold Lava Men. Other known Lava Men have included the golden Lava Men Akor, Danka, and Kelak, as well as the deceased Molto. Enemies of the Lava Men have included the Avengers, Thor, the Molian and Tyrannoid Subterraneans, Brutus, and theDeviants. Major allies of the Lava Men have included Grotesk, Captain Marvel II, and formerly Cha'Sa'Dra.
Molto appeared on Earth's surface, and battled Thor in New York City. Molto became Thor's friend afterwards, however.The Avengers later fought the Lava Men in Subterranea when they tried to force a 'living rock' that was emitting deadly sound waves to the surface, hoping that when it eventually exploded it would wreck Earth and not their realm. However the Hulk was tricked into striking the spot that destroyed it. Thor allowed the rest of the Lava Men to return home.
Jinku plotted to use the Mole Man's machine to activate all volcanoes on the Earth. Molto was mortally wounded by Jinku, but warned Thor and the Human Torch about Jinku before dying. Thor wrecked the machine, and the Torch led the Molion Subterraneans in defeating the Lava Men.
A Project: Pegasus borer probe wreaked havoc in a Lava Men settlement, and they retaliated by invading Project: Pegasus. The Lava Men clashed with the Avengers again before returning to Subterranea. The Lava Men became involved in a war against the other Subterranean races, and managed to capture the Mole Man.
Jinku magically created a group of non-sentient Lava Men that attacked the Avengers and Hydro-Base. It was revealed how the demon Cha' Sa' Dra transformed a group of Gortokian subterraneans into the first Lava Men, and how Cha' Sa' Dra's death killed hundreds of Lava Men, and placed others in an immobile "chrysalis" state. The vengeful Jinku unleashed a monster against the Avengers in Subterranea. The immobile Lava Men attained new golden forms, and Jinku was similarly transformed. However, they all made peace with the Avengers.
Lava Men have a high resistance to extreme heat and flame. They continually generate intense heat from their bodies and can increase the amount of heat at will, enough to be able to melt a weapon in its vicinity. They have a mystical ability to cause large amounts of volcanic ash to appear, seemingly from nowhere, and to transform metal into ash. They also have an immunity to aging. Some Lava Men can mystically transform themselves into 20-foot-tall (6.1 m) giants composed of hardened lava. Some Lava Men can mystically command molten lava to do their bidding by performing a ritual prayer to thedemons they worship. The golden Lava Men can transform their shapes, and in doing so, even merge their bodies with one another. They once formed themselves into a large sphere that could defy gravity. Jinku has mystically created non-sentient Lava Men which possess the superhuman powers of the real Lava Men.
Lava Men had unusually acute hearing and night vision to enable them to function more easily in the darkness of Subterranea.