Supergirl's Greatest Challenge is a Supergirl/Legion of Super-Heroes story published in Action Comics #287 (April, 1962). It was authored by Jerry Siegel and Jim Mooney.
Linda Danvers/Kara Zor-El is dealing with her present-day problems when she receives an emergency call of the Legion of Super-Heroes. Upon arriving in the 30th century, Supergirl is informed that a planet-destroying Eldritch Abomination (called Positive Man by the Legion due to its human-like energy body being composed of positive ions) is heading towards Earth with the intent to wipe the planet out.
Kara manages to stop the monster, but the Legionnaires have been suddenly and mysteriously depowered, a misfortune that they blame on radiation fallout caused by the destruction of the creature's energy body. Whatever the case may be, nobody can know the Legion has become powerless, so Supergirl comes up with the idea to cover up for her teammates until they get their powers back.
Supergirl begins following several Legionnaires around, using her powers to solve their cases behind the scenes. Unfortunately, Kara does not realize what her friends have been sneakily repaced by pretenders who are setting a trap for her. And if she is not capable of springing out of it, the Legion and the world will be doomed.
This story was reprinted in the Supergirl - The Silver Age omnibuses and trades and referenced in the Supergirl (2005)'s 2010 Annual.
Tropes:
- Action Pet: Streaky's descendant Whizzy uses his telepathic powers to help Supergirl.
- Animalistic Abomination: A planetary explosion caused by a doomsday device turned a laboratory bird into a humongous energy being who is powerful enough to destroy planets by accident. Despite its body being a white mass of positive ions -which led Kara to call it Negative Creature-, it still looks like a giant bird of prey.
- Apocalypse How: Supergirl is about to square off against the Positive Man when the eldritch creature deliberately changes its course and passes through an inhabited world, blowing it up.
- As You Know: When Supergirl arrives, Saturn Girls tells they need her help to deal with a new threat because "You have many superpowers while we have only one power each". Two facts they know their old friend and teammate is obviously aware of.
- Attack of the 50-Foot Whatever: Positive Man and the Negative Creature are one alien humanoid and an extraterrestrial bird turned into planet-sized energy monsters.
- Brought Down to Normal: Subverted. The entire Legion have apparently lost their powers, and Cosmic Boy suggests the cause might be radiation fallout caused by the explosive collision of two eldritch abominations. However, it turns they were an alien race of shapeshifters impersonating the Legionnaires.
- Curb-Stomp Battle: Without the surprise factor or a Phantom Zone Projector, the Chameleon Men can do nothing but whine impotently as Kara kicks them out of the Legion's base.
- Deadly Dodging: Kara cannot attack directly Positive Man and the Negative Creature due to their intangible bodies being composed of sheer energy; so that Kara baits the Creature into chasing after her, flies towards Positive Man and then gets out of the way rapidly, with the result that both abominations collide with each other and their energy bodies explode.
- Distress Call: The real plot begins when Kara receives a call of the Legion of Super-heroes summoning her to the 30th century.
- Earth-Shattering Kaboom: Positive Man is destroying inhabited worlds across the cosmos out of envy towards all living creatures. Before Supergirl have time to find a way to stop it, it blows up an inhabited planet -merely by passing through it- before her eyes.
- Energy Beings: The intangible bodies of Positive Man and the Negative Creature are composed of positive and negative ions, respectively.
- Free-Range Children: Fred and Edna Danvers do not even blink when their adoptive teen daughter, who has just returned home, tells she must leave immediately for the 30th century to face some kind of life-threatening danger.
- Halfway Plot Switch: After the three first pages, the plot changes from Supergirl trying to protect her secret identity from Midvale's Superman fans and other interlopers to answer the summons of the Legion and travel to the far-future to fight a cosmic horror and bust a ploy to destroy the team.
- Humanoid Abomination: A planetary explosion caused by a doomsday device turned a mad scientist into a humongous energy being who hates life and roams the cosmos obliterating inhabited worlds by merely passing through them. Despite its body being a white-outlined, translucent and intangible mass of positive ions -which led the Legion to call it Positive Man-, it still looks like a giant, four-limbed, bipedal humanoid.Supergirl: "There he is... The Positive Man! A destructive force which was once— human! That mind-tape revealed he was once an alien scientist who blew up his planet while creating a doomsday bomb! The explosion transformed him into this terrible menace! Envious of all life, he roams the cosmos jealously, destroying inhabited worlds!"
- Identical Grandson: Whizzy looks so much like his very distant ancestor Streaky the Supercat Supergirl initially mistakes him with her cat. They even share the same fur color and distinctive yellow lightning bolt marks on their sides.
- Inconsistent Coloring: In the second panel of the seventh page the colorist seems to have forgotten that Supergirl does not wear pants, since her legs are colored blue.
- Kill and Replace: A band of alien invaders called the Chameleon Gang knock the Legion out and shape-shift into the Legionnaires to impersonate them. However, Supergirl manages to unmask and capture them before they get to kill the real Legion.
- Little Green Men: The Chameleon Men are an alien race of short, hairless, pointy-eared, green-skinned humanoids who intend to get rid of the Legion to conquer Earth.
- Luckily, My Powers Will Protect Me: As heading to the Legion meeting, Kara wonders why she has been summoned, she ponders it will be good to see her friends again, and out of nowhere she thinks "Each of them possesses one super-power!"
- Mass "Oh, Crap!": The Chameleon Men's become horrified when Kara is pulled out of the Phantom Zone where they had previously banished her into.
- No-Sell: Positive Man's energy body is composed of positive ions and can disintegrate anything it touches. Supergirl's invulnerable body, though, can touch it and remain unharmed because of her invulnerability.
- Now, Let Me Carry You: When the Legionnaires apparently lose their powers, Supergirl, who is usually a backup/part time member, must cover up for the whole team.
- Omnicidal Maniac: The Positive Man wanders around the universe destroying inhabited worlds out of envy and hatred towards all living creatures.
- Pineal Weirdness: To get Supergirl up to date on the pending crisis, the Legion uses a future-tech device to download the info into her "'Third Eye' pineal gland."
- Planet Destroyer: Positive Man destroys inhabited worlds by passing through them.
- Poster-Gallery Bedroom: Linda's friend Margie is president of Midvale's Superman fan club and has her room filled with posters, pictures, statuettes and other merchandising of Superman.
- Put on a Bus: Whizzy, descendant of Streaky the Supercat in the 30th century, makes his first appearance, helps Supergirl out, and is never seen again.
- Right in Front of Me: As giving a speech for Midvale's Superman fan club, Lois Lane casually mentions she has also partnered with Supergirl...who coincidentally looks right like Miss Linda Danvers. Linda winces inwardly, feeling thankful for her brown wig concealing her identity.
- Rule of Perception: As Supergirl's Legion figurines are sending their distress call, their heads are crowned by a halo of black lines to mean they are glowing.
- Sacrificial Planet: The Positive Man obliterates an unnamed inhabited world by merely passing through it on his way to Earth.
- Shockwave Clap: When some forest rangers are about to blow up a tree stump (which is concealing Kara's secret base's tunnel entrance) secret tunnel), Supergirl fakes the sound of a thunder by powerfully clapping her hands as shooting her eye beams at the dried-up trunk. Her trick makes the rangers believe that a lightning bolt has destroyed the stump for them.Supergirl: "The Rangers aren't looking at the stump! I think I can get away with my trick! I'll project my heat-vision downward at the same time fake the sound of thunder by clapping hands!"
- Spanner in the Works: The Chameleon Men's scheme to get rid of the Legion fails because before being banished into the Zone Supergirl had run into her super-powered cat's descendant Whizzy, who decided to follow her around. After being accidentally dumped into the Zone together with Supergirl, Whizzy telepathically influences a robot-maker into building a Chameleon android who infiltrates the invaders' lair, finds the Projector and releases Supergirl.
- Telepathy: Whizzy the Supercat can communicate with humans telepathically.
- They Look Like Us Now: The green-skinned, pointy-eared Chameleon Men shape-shift into human forms to destroy the Legion and infiltrate Earth.
- Thrown Down a Well: A race of shape-shifting aliens steals a Phantom Zone Projector to send Supergirl into the eponymous pocket dimension.
- Time Travel: Kara is summoned to the 30th century by a distress call sent by the Legion of Super-Heroes.
- Too Powerful to Live: Positive Man crumbled planets to dust simply by passing through and could not be harmed by conventional means, so it never appeared again after Supergirl found a way to break his energy body down.
- Treants: The Tree Men from the planet Arbro are towering, yellow-barked, sapient humanoid trees whose species is facing extinction due to their homeworld orbiting a dwindling star.
- Was Once a Man: Positive Man was a human (mad) scientist before being turned into an energy-based eldritch abomination by an experimental exploding planetary bomb.
- What Measure Is a Non-Human?: When Supergirl finds an eldritch abomination who used to be a man before being turned into a planet-destroying energy being, she immediately decides he must be destroyed, using another eldritch abomination as a nuke to break its body down. Kara does not seem concerned about both entities being technically alive, or the second creature being destroyed despite having apparently done nothing to deserve it.
- Zeerust: The only differences between 1962 video cameras and their 30th century equivalents are that the latter are considerably bulkier, more unwieldy, and have attached metal fins.
