Promethium is the name used for two different fictional substances; one from the DC Comics

DC Comics

DC Comics, Inc. is one of the largest and most successful companies operating in the market for American comic books and related media. It is the publishing unit of DC Entertainment a company of Warner Bros. Entertainment, which itself is owned by Time Warner...

 universe

DC Universe

The DC Universe is the shared universe where most of the comic stories published by DC Comics take place. The fictional characters Superman, Batman and Wonder Woman are well-known superheroes from this universe. Note that in context, "DC Universe" is usually used to refer to the main DC continuity...

 and one from the Marvel Comics

Marvel Comics

Marvel Worldwide, Inc., commonly referred to as Marvel Comics and formerly Marvel Publishing, Inc. and Marvel Comics Group, is an American company that publishes comic books and related media...

 universe

Marvel Universe

The Marvel Universe is the shared fictional universe where most comic book titles and other media published by Marvel Entertainment take place, including those featuring Marvel's most familiar characters, such as Spider-Man, the Hulk, the X-Men, and the Avengers.The Marvel Universe is further...

. These should not be confused with promethium

Promethium

Promethium is a chemical element with the symbol Pm and atomic number 61. It is notable for being the only exclusively radioactive element besides technetium that is followed by chemical elements with stable isotopes.- Prediction :...

, which is an actual chemical element.

Depleted promethium

In DC Comics

DC Comics

DC Comics, Inc. is one of the largest and most successful companies operating in the market for American comic books and related media. It is the publishing unit of DC Entertainment a company of Warner Bros. Entertainment, which itself is owned by Time Warner...

, promethium was invented and patented by Steve Dayton of Dayton Industries. When alloy

Alloy

An alloy is a mixture or metallic solid solution composed of two or more elements. Complete solid solution alloys give single solid phase microstructure, while partial solutions give two or more phases that may or may not be homogeneous in distribution, depending on thermal history...

ed with titanium

Titanium

Titanium is a chemical element with the symbol Ti and atomic number 22. It has a low density and is a strong, lustrous, corrosion-resistant transition metal with a silver color....

 and vanadium

Vanadium

Vanadium is a chemical element with the symbol V and atomic number 23. It is a hard, silvery gray, ductile and malleable transition metal. The formation of an oxide layer stabilizes the metal against oxidation. The element is found only in chemically combined form in nature...

, it forms a near-invulnerable metal

Metal

A metal , is an element, compound, or alloy that is a good conductor of both electricity and heat. Metals are usually malleable and shiny, that is they reflect most of incident light...

. The bionic and cybernetic components of Vic Stone (better known as Cyborg

Cyborg (comics)

Cyborg is a fictional character, a superhero appearing in comic books published by DC Comics. The character was created by writer Marv Wolfman and artist George Pérez, and first appears in a special insert in DC Comics Presents #26...

) are made out of depleted promethium, and Red Arrow

Roy Harper (comics)

Roy Harper is a fictional superhero in the DC Comics Universe. He was known for over fifty years as Green Arrow's teenage sidekick Speedy. He first appeared alongside his mentor in More Fun Comics #73...

 of the Justice League

Justice League

The Justice League, also called the Justice League of America or JLA, is a fictional superhero team that appears in comic books published by DC Comics....

 wears a bodysuit that combines both depleted promethium and Kevlar

Kevlar

Kevlar is the registered trademark for a para-aramid synthetic fiber, related to other aramids such as Nomex and Technora. Developed at DuPont in 1965, this high strength material was first commercially used in the early 1970s as a replacement for steel in racing tires...

; Deathstroke

Deathstroke

Deathstroke the Terminator , originally simply the Terminator, and known by the Teen Titans as Slade, is a fictional character, a supervillain and sometimes antihero in the DC Comics Universe. He is a mercenary and assassin who first appeared in The New Teen Titans #2...

 the Terminator's mesh armor, sword and staff are made (either wholly or in part) of depleted promethium.

Volatile promethium

Promethium is also capable of generating near-limitless amounts of energy

Energy

In physics, energy is an indirectly observed quantity. It is often understood as the ability a physical system has to do work on other physical systems...

, and so can be used as a power source for many gadgets. Volatile promethium is also a dangerous mutagen

Mutagen

In genetics, a mutagen is a physical or chemical agent that changes the genetic material, usually DNA, of an organism and thus increases the frequency of mutations above the natural background level. As many mutations cause cancer, mutagens are therefore also likely to be carcinogens...

 that can be used to mutate living beings or trigger their metagene

Metahuman

Metahuman is a term to describe superhumans in DC Comics' shared universe, the DC Universe. It is roughly synonymous with both mutant and mutate and posthuman in the Wildstorm and Ultimate Marvel Universes. Use of the term in reference to superheroes was coined in 1986 by author George R. R...

; Dayton used it when creating the super-powered criminals known as the Hybrid

Hybrid (DC Comics)

The Hybrid are a fictional group of supervillains appearing in DC Comics. Their first appearance as a group was in New Teen Titans vol. 2, #24, which was marketed in October 1986...

.

Marvel Comics

In Marvel Comics

Marvel Comics

Marvel Worldwide, Inc., commonly referred to as Marvel Comics and formerly Marvel Publishing, Inc. and Marvel Comics Group, is an American company that publishes comic books and related media...

, promethium is a magical metal found only in Belasco

Belasco

Belasco is a fictional supervillain in the Marvel Comics Universe. The character's first appearance was in Ka-Zar the Savage #11; he was created by Bruce Jones and Brent Anderson.-Fictional character biography:...

's dimension, known as Otherplace

Otherplace

Otherplace, is a fictional location in titles published by Marvel Comics. The concept debuted in Uncanny X-Men #160, and was created by Chris Claremont and Brent Anderson.-History:...

. In Otherplace, it takes the form of a giant animal heart, hidden in a cavern deep below its surface. Removal of the promethium to another dimension will cause Limbo to vanish. The heart of Limbo was once sought by the supervillain Doctor Doom

Doctor Doom

Victor von Doom is a fictional character who appears in Marvel Comics publications . Created by Stan Lee and Jack Kirby, the character first appeared in Fantastic Four #5 wearing his trademark metal mask and green cloak...

 as an inexhaustible energy source for his nation of Latveria

Latveria

Latveria is a nation in the . It is an isolated European country ruled by the supervillain Doctor Doom, supposedly located in the Banat region. It is surrounded by the Carpathian Mountains, and also borders the Symkaria to the south. Its capital is Doomstadt.-Publication history:Latveria first...

. It is currently in the possession of Darkoth

Darkoth

Darkoth is a fictional character, supervillain appearing in the Marvel Comics universe. His first appearance was in Fantastic Four series 1 #142, , and he was created by Gerry Conway and Rich Buckler....

.

The Marvel UK

Marvel UK

Marvel UK was an imprint of Marvel Comics formed in 1972 to reprint US produced stories for the British weekly comic market, though it later did produce original material by British creators such as Alan Moore, John Wagner, Dave Gibbons, Steve Dillon and Grant Morrison.Panini Comics obtained the...

 cyborg

Cyborg

A cyborg is a being with both biological and artificial parts. The term was coined in 1960 when Manfred Clynes and Nathan S. Kline used it in an article about the advantages of self-regulating human-machine systems in outer space. D. S...

 character Death Metal

Death Metal (comics)

Death Metal is a character from the Marvel UK imprint of Marvel Comics. He first appeared in Death³ #1 and was created by Dan Abnett and Dell Barras.-Fictional character biography:...

 is also made of a magical metal called Promethium; it is not clear if this is the same material or if the name is simply a coincidence.

Other media

In Spider-Man: The Animated Series

Spider-Man (1994 TV series)

Spider-Man, also known as Spider-Man: The Animated Series, is an American animated series starring the Marvel Comics superhero, Spider-Man. The show ran on Fox Kids from November 19, 1994, to January 31, 1998. The producer/story editor was John Semper, Jr. and production company was Marvel Films...

, promethium X is a previously unknown element found on the Moon in conjunction with the Venom Symbiote

Venom (comics)

Eddie Brock is a fictional character created by David Michelinie and Todd McFarlane. A comic book supervillain, Brock's earliest appearance is a cameo in Web of Spider-Man #18 before making his first full appearance in The Amazing Spider-Man #299 as Venom...

 by astronaut John Jameson

John Jameson (comics)

John Jameson is a fictional character in publications from Marvel Comics.-Publication history:...

. It is a black rock slightly larger than a fist, that looks similar to coal.

Alistair Smythe

Alistair Smythe

Alistair Smythe is a comic book supervillain, owned by Marvel Comics and existing in that company's Marvel Universe. He was one of the main foes of Spider-Man...

 (then still a regular human in a hoverchair) discovered its first unusual property: normally inert, Promethium X when exposed to high temperatures, will react with an atomic explosion, making it a perfect untraceable terrorist weapon.

The second unusual property, however, was discovered by Spider-Man

Spider-Man

Spider-Man is a fictional Marvel Comics superhero. The character was created by writer-editor Stan Lee and writer-artist Steve Ditko. He first appeared in Amazing Fantasy #15...

. Promethium X gradually transmutes itself into lead. The series never specifies what it was reacting to, but since it remained on the Moon as promethium X, it can be assumed the catalyst is something it encountered on Earth, such as oxygen

Oxygen

Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...

, nitrogen

Nitrogen

Nitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...

, sound

Sound

Sound is a mechanical wave that is an oscillation of pressure transmitted through a solid, liquid, or gas, composed of frequencies within the range of hearing and of a level sufficiently strong to be heard, or the sensation stimulated in organs of hearing by such vibrations.-Propagation of...

, or ambient warmth.

In the Iron Man (2008) game a Prometheus Missile is seen and mentioned. Due to its name the missile could have been made out of this metal.

In the Batman: The Brave and the Bold

Batman: The Brave and the Bold

Batman: The Brave and the Bold is an American animated television series based in part on the DC Comics series The Brave and the Bold which features two or more super heroes coming together to solve a crime or foil a super villain...

episode "Deep Cover for Batman!" promethium-90 is an important component in a bomb the Injustice Syndicate of an alternate Earth

Multiverse (DC Comics)

The DC Multiverse is a fictional continuity construct that exists in stories published by comic book company DC Comics. The DC Multiverse consists of numerous worlds, most of them outside DC's main continuity, allowing writers the creative freedom to explore alternative versions of characters and...

 plans to use to destroy all life on the main alternate universe

Parallel universe (fiction)

A parallel universe or alternative reality is a hypothetical self-contained separate reality coexisting with one's own. A specific group of parallel universes is called a "multiverse", although this term can also be used to describe the possible parallel universes that constitute reality...

 Earth the show takes place on (Earth-23).

It is also in the Warhammer 40,000 universe as a liquid fuel used in most land based vehicles and short range "flamethrower style" weapons.

Promethium is also present in the MMORPG

MMORPG

Massively multiplayer online role-playing game is a genre of role-playing video games in which a very large number of players interact with one another within a virtual game world....

 RuneScape

RuneScape

RuneScape is a fantasy massively multiplayer online role-playing game released in January 2001 by Andrew and Paul Gower, and developed and published by Jagex Games Studio. It is a graphical browser game implemented on the client-side in Java, and incorporates 3D rendering...

, as the strongest metal available in Daemonheim.