Captain Universe

Captain Universe is a Marvel Comics character, and one of the few truly unique superhero concepts. Specifically, Captain Universe was a superhero identity that kept changing hosts- by itself! The character's tagline was "The hero who could be YOU!"

To be precise, Captain Universe was actually a semi-sentient cosmic force called The Unipower, whose main purpose was to maintain the barrier between Earth and another universe in place. Secondarily, it would grant powers to single individuals temporarily so they could fulfill specific missions. Curiously, these missions ranged everywhere from saving the world to rescuing single, normal individuals.

The concept was introduced in The Micronauts comic book series. The first Captain appearing in issue #8 (August, 1979), created by Bill Mantlo and Michael Golden. It was established there that the universe the heroes came from, The Microverse, was separated from Earth's by a "space wall" that had to be supported on both sides. On the Microverse it was maintained by the "Enigma Force" that was wielded by Commander Rann, the Micronauts leader; on Earth however, there was no specific wielder for the Enigma Force's counterpart, for some reason. Instead the Unipower sustained itself by jumping from one person to another. Such a person would gain the powers and costume of Captain Universe, along with knowledge of the mission he or she had to fulfill (but no direct communication with the Unipower); afterward its completion the host would return to normal.

Captain Universe is more a plot device than a character, since it has no regular host and the Unipower itself is rarely seen speaking (this varies by writer, however.) It's mostly used to power up heroes when needed, or to give normal people a taste of what it's like to be a superhero even if only for a short while. The concept's most famous use probably was in the Story Arc where Spider-Man gained its powers (but not its costume or knowledge of where they came from, due to a freak accident) leading the hero to gain Superman-level powers during the Acts Of Vengeance Crisis Crossover, where supervillains switched enemies, and thus gave Spidey a chance against much more powerful villains than he usually battled.

The "character" has also starred in at least one miniseries.

Tropes related to Captain Universe:

 * Another Dimension: Where the Space Wall and The Microverse are located.
 * Heroic Host: Different in that that entity bonds with a different person each time, until recently.
 * Humans Are Special: apparently, since saving even single lives seem to matter to the Unipower. Guess it just likes us.(Note that in at least one case, an alien became Captain Universe.)
 * Powers Via Possession: Though the Unipower doesn't really force the host to do anything, only tells him what he has to do. Presumably if you disobey, it'll just leave you.
 * Steve Ditko: Co-created the character with Bill Mantlo.
 * Story Breaker Power: The Unipower-powered Spider-Man punched the friggin' Juggernaut (bitch!) out of New York City!
 * One story had The Incredible Hulk gain its powers!!
 * Superpower Lottery: You win it!! For a few minutes anyway.
 * You Suck: Inverted- anyone can be Captain Universe, even an old man in a coma.