Quite possibly Most Common Superpower incarnate.The 1970s version of All-Star Comics, starring the Justice Society of America, featured the original versions of many of DC Comics' superheroes and their families, living in a parallel universe known as Earth-2. In issue #58 (January-February, 1976) a new character debuted, created by Gerry Conway, Ric Estrada, and Wally Wood. Power Girl was introduced as the counterpart of Supergirl- she was the cousin of Earth-2's Superman (Kal-L). It was decided to make her as different as possible from Supergirl - including a different costume, code-name, personality and (most notably) a sexier body.Karen Starr, the name she adopted, proved a hit with readers. She received solo stories in "Showcase" #97-99 (February-April, 1978). DC was considering launching a Power Girl series. But in 1978, the DC Implosion struck, with the cancellation of over 24 ongoing titles. There was no room for new titles. Karen did however become a founding member of Infinity, Inc.. Regularly appearing in the 12 first issues of said series, and occasionally turning up in subsequent ones.And then Crisis on Infinite Earths hit and not only wasn't there an Earth-2 anymore, but Superman was now again the last Kryptonian. Power Girl still existed, and though, was given a new origin as an Atlantean. After some silly retcons, including one period where she was vulnerable to "natural, unprocessed materials,"Infinite Crisis and a Power Girl mini-series finally cleared up her origin by having her be... the cousin of the Earth-2 Superman (after reality got Cosmic Retconned again).She was a member of the Justice Society of America and had her own comic book, started in 2009, originally written by Justin Gray and Jimmy Palmiotti and beautifully drawn by Amanda Conner. After issue #12 the original creative team left the series, replaced by Judd Winick and Sami Basri, and the series shifted both its visual and writing style. In her series, she reestablished her Secret Identity of Karen Starr and established the company Starrware, all the while mentoring Atlee, the new Terra, and trying to stop the Ultra-Humanite or really hot aliens from destroying New York. The series took a Lighter and Softer approach to the character and the DC Universe at large, at first focusing on Power Girl's attempts to reintegrate into living a normal life and forming a stable relationship with Terra. After the creative team change, the book focused less on Power Girl's personal life, instead revolving around her heroic activities and how they affected her personal life, and also dealt with the reappearance of Maxwell Lord. The story was heavily tied into the Brightest Day event, though not published under the Brightest Day banner, and had interweaving plotlines with Justice League: Generation Lost.After the "New 52" DC Universe reboot, Power Girl reappeared as Karen Starr, at first in a supporting role for Mister Terrific, and later in an ongoing series with the Huntress, a new volume of ''World's Finest'', where she is revealed to be ...the cousin of the Earth-2 Superman. This time, however, she has been explicitly described as the Supergirl of Earth-2, having started her superhero career as Supergirl when she was younger, before coming to Prime Earth together with Huntress (who served as the Robin of Earth-2). Controversially, the New 52 version of Power Girl lacked her iconic costume for the year or so, but before long the writers (either because they planned it all along or because of public demand) had her sporting the famous cleavage window again.
All of the above, for the most part, apply to her so called "classic" costume, an attempt to create a new costume without the Cleavage Window was made when the DCU was rebooted in the New 52, but that lasted for about a year before she got a variant of her classic costume back.
Amnesiac Dissonance: After his final defeat, Ultra-Humanite had his memory erased and was reintroduced into society. He does not seem happy with the plan, but he is accepting of the future...until Power Girl turns him back and he swears that it will never be over between them. It is unknown how much of his original nature will remain after his mind wipe.
Art Shift: When the original creative team left her series in 2010 there was a change in style adapted by the new pencilers and inkers. The bright colors of Amanda Conner were dropped, replaced with the more subdued palette of Sami Basri, and the character designs became slimmer, losing the pronounced curves of the early issues.
Baleful Polymorph: Power Girl, Superman and Zatanna are briefly turned into rock people by Siphon, who can copy Zatanna's powers.
Berserk Button: Kara is very protective of Terra, her sidekick/sister-figure.
Big Bad: When breaking into New Cadmus, which is being orchestrated by Max Lord, Kara and Nico actually comment that this is the headquarters of the bag guy that is behind everything.
Brainwashed: Max Lord hits Power Girl with a mental suggestion to go kill the Justice League International. She sees everyone on the team as another hero (Captain Atom as Superman, Fire as Starfire, Ice as Supergirl, Rocket Red as Green Lantern Hal Jordan and Booster Gold as Batman) and hears all their dialogue as plans to conquer and rule humanity.
Captain Ersatz: Vartox was originally based on Sean Connery, with his appearance taken from the movie Zardoz and his over-the-top machismo from Connery himself.
Card-Carrying Villain: "'Rue the day'? Nobody talks like that anymore. It just sounds stupid." "It's a classic villain line."
Character Development: From her "victim to raw materials" days in the 90s, she was brought into the Justice Society of America and eventually became its Superman equivalent (until Earth-22 Superman arrived) and, later, the team's first chairwoman.
Characterisation Marches On: In her very earliest appearances in All Star Comics Power Girl was presented as kind of a brash young hot head with a a serious chip on her shoulder. She lacked a civilian identity entirely and while she was never depicted as Dumb Muscle she wasn't shown to be particularly brilliant either - her Genius Bruiser traits came later thanks to a 'memory teacher' borrowed from Wonder Woman implanting vast knowlege of computers into her mind.
Chest Insignia: A notable lack of one, she has what is termed a "boob window." Because of her long and complicated history there have been numerous explanations as to why, exactly, she has this window. The current story behind it is kind of sad - she could not think of a symbol, so she left it blank and never filled it and is actually undergoing a minor identity crisis as she tries to figure out where she fits in the world. Though not all reasons have been as poignant, they are all intentional and rational. Previously, one of her explanations was that the window gave a clear indication of who and what she was: Strong, feminine and yes, big-breasted. If people were overly preoccupied or distracted by the last part that was their problem, not hers, she would not be bound by what they thought of her.
The New 52 version has a stylized P on the left side of her chest on the costume she wore before she switched over to the variant of her pre-New 52 version's "boob window" costume.
Chuck Cunningham Syndrome: After the author/artist switch to Judd Winick and Sami Basri, Terra, who had been Power Girl's sidekick/partner/sister throughout the early issues, is neither seen nor mentioned.
Continuity Snarl: Power Girl's origin is unusual in that it lampshades the utter failure of past writers to come up with a legitimate way of maintaining her character's existence in the face of endless rewrites of the DC universe's history. There is no way the character can exist in the currently "valid" history- and her character development directly involves her attempts to deal with that fact. She is the cousin of Earth-2 Superman, but it is explicitly the pre-Crisis Earth 2. The new similar Earth-2 created following the 52 event has its own Power Girl cementing our Power Girl's status as an orphan of the old Multiverse.
Crossover: Issue #20 is directly continued in Justice League: Generation Lost, which follows up on Power Girl's brainwashing at the hands of Max Lord to kill the Justice League International.
Curb-Stomp Battle: Once Power Girl is pushed past her limit and stops holding back she takes Ultra-Humanite, who a few pages earlier had been bragging about destroying all of civilization, and beats him down in six panels. Four of those panels are PG slamming his head against the wall.
Cut Lex Luthor a Check: Deconstructed. Power Girl (In her role as Karen Starr, head of Starrware) holds the patents to several miraculous technologies and heads what seems to be a well-running corporation. However, now that they have engineered these miraculous technologies they need to develop them into some form of marketable product, deal with worried overseeing government agencies and also contend with the almost insurmountable issues of normal office paperwork. Starrware might be on the cutting edge of human technology, and its stock prices will probably go through the roof once it goes public, but right now it needs to find some way to actually gain revenue from its assets. Power Girl herself is struggling to make ends meet until the profits start to come in, and lampshades this when fighting the Blue Snowman, who had developed the technology to create weather and was using this technology to steal jewels not worth half of what her equipment was worth.
Distaff Counterpart/Evil Counterpart: Power Boy, who wears a black version of her outfit except his costume doesn't have sleeves and covers his legs. He also was abusive to Supergirl during the brief period they dated.
Dressed in Layers: Though Power Girl herself is always prepared for trouble, Terra has not quite grasped the concept that she always needs to wear her costume underneath her clothing just in case. As such, she is completely unprepared when a monster rises up when she and PG are out watching a movie and she ends up going into battle dressed only in adorable lady-bug underwear.
Note that the writer actually put effort into making it plausible for PG.
Dumb Blonde: the ultimate "first impression" trope, especially for readers coming into the pre-New 52 series cold. In truth, the trope has been subverted and averted and occasionally lampshaded constantly since the character was first introduced.
Evil Brunette Twin: "Divine," the evilclone of Power Girl, has black hair opposed to PG's blonde, but is otherwise identical in every way.
Eviler than Thou: Satanna goes to Dr. Sivanna to get a weapon to revenge herself on Power Girl and gives him what he wanted as payment. Afterwards he attempts some minor small-talk and she, because she and he are villains, does not feel it is necessary to disguise the fact that she felt this was a heartily disgusting event which she did solely as part of a business exchange. He agrees with her, then points out that since they are bad guys he no longer cares about her desires since she gave him what he wanted, and throws her out the window.
Evil Laugh: Apparently, characters differentiate between your Mad Scientists and scientists who happen to be mad by the presence or absence of a good "Moo-Ha-Ha!"
Fetus Terrible: Prior to the Zero HourCrisis Crossover, Power Girl became mysteriously pregnant, and during the crossover, she gave birth to a son named Equinox, who managed to defeat the Big Bad, Scarabus, in an issue of Justice League America and was never seen nor mentioned again. And the father is... Arion, who was her grandfather at the time this was published. Like many things from the Gerard Jones JLA run, this has been one of those things quietly allowed to fade from DCU history and fan memories. Letter column remarks back in the day seemed to unofficially indicate that such stories were definitely not going to be touched again.
Flying Brick: After finally being established (again) as Superman's cousin she gets most of his powers as well, including heat vision and ice breath.
Gendered Outfit: Power Boy, who wears a tank top unitard rather than Power Girl's leotard.
Genre Savvy: Zatanna has a "magic line," a phone number for people to call when they are facing life-threatening circumstances from magical adversaries. Because any phone call to that number would logically be of the highest importance she always answers when somebody calls. As such, her voice-mail recording for that number is an explanation that she must be in terrible danger, since she would never chose to not pick up the phone, and whoever is calling should track her phone GPS and come rescue her right away.
Homage Shot: At one point when Atlee and Power Girl are at the movies, the main cast of The Big Bang Theory are seen, most notably Howard, who then proceeds to hit on her. And strike out. HARD.
How Do I Shot Web?: Power Girl actually discusses this trope when fighting her evil clone. She reasons that, even if "Divine" has all the same powers as her that does not mean she knows how to use those powers, since she has only been "alive" for ten minutes and has never worked with these abilities before.
TerraUltra-Humanite: "Let's have one of those totally clichéd hero-slash-friend fights. You get to say things like 'I know you're stronger than this', or 'You can fight it'...oh, and 'This isn't you!'"
In Power Girl's crossover with Justice League: Generation Lost Power Girl has been brainwashed into believing that the members of the Justice League International are other heroes planning to conquer and rule humanity. The members of JLI, dreading the destruction and loss of life that would come from fighting Power Girl in earnest (Assuming they could survive such a fight), try to get through the brainwashing and have her recognize them.
Kick the Dog: Ultra-Humanite and Satanna are already well past the Moral Event Horizon, they were murderers and psychopaths long before this series started, but when they put Atlee's brain inside the burned gorilla body it is just wrong.
Lampshade Hanging: Atlee seems to derive nourishment from all the lamps she keeps pointing out:
Large Ham: Vartox is either the single greatest event to happen to comic-books since an artist thought "Wait a second, I can make them as big as I want," or he has come to murder all Power Girl fans with overexposure to the "sexy superstud from planet Valeron."
Vartox: "Bask in the seduction musk distilled from tears of the ghost poets of dimension seven...to prove his manly prowess, Vartox has arranged for a demonstration of masculinity."
Porn Stache: Vartox rocks a 'stache the likes of which Earth is not prepared for.
The Real Heroes: Power Girl managed to squeeze one in. When a firefighter is helping her limp away from a bomb crater he comment that he does not often get the opportunity help somebody like her ("Like me?" "Yeah... a hero") and she replies "I can say the same thing about you."
Reality Warper: Who turns out to be a young girl who reads a lot of fantasy.
Reed Richards Is Useless: Averted with Karen Starr and Starrware, who have managed to create some really cool technology, sometimes by reverse engineering alien tech. This includes nanotech that can create a 1966 Pontiac GTO from what appears to be a pile of rubber, scrap metal and rope. With a vanity plate already installed ("Starr"). Say what you will, Power Girl has style.
Strange Minds Think Alike: When Zatanna is in the presence of a man who can copy her powers, she realizes that just beating him in a Wizard Duel will not solve the problem, she needs to physically leave his presence to keep him from getting her powers permanently.
Zatanna: (In Narration) He's good right out of the gate. I'm just better. But being better isn't really the issue, I just need to get the heck away from this idiot! Power Girl: "We need to get Zatanna the heck away from that idiot!"
Straw Feminist: Has come across as one in the past, but has mellowed out since then. Her past behavior was retconned as a diet soda allergy.
Squick: Power Girl's in-universe reaction to learning that the Ultra-Humanite had sex with his girlfriend Satanna... in gorilla form. Because Satanna was turned on by his new body.
Stripperiffic: Despite the notoriety of her costume, it is actually rather tame by modern standards (it more or less looks like a swimsuit), and the lack of protection is somewhat justified considering she is bulletproof.
Power Girl: "No! No, you didn't!! You cloned Krypto?!?! What kind of sick @#$#$—this is Superman's dog. For crying out loud! Is nothing sacred!?"
After Power Girl, Superman and Zatanna are turned into rock people she looks down at her new rocky body and comments that "this is wrong on many, many levels."
Tsundere: Power Girl herself during the Justice League Europe arcs. Considering the one who got her dere side was the only one who didn't spend all his time ogling her, probably justified.
Underwear of Power: Her normal costume is a pretty standard superheroine outfit, but Terra has not yet grasped the importance of always having your costume handy and one time she was forced to go into battle wearing nothing but adorable lady-bug underwear when she and Power Girl were attacked while out at the movies.
Urban Legend: In Real Life, there is a long-lasting myth that Power Girl has such impressive powers because Wally Wood, one of her original artists, was playing a joke on/testing his editors. The story goes that he drew her steadily larger from issue to issue after her first appearance, trying to see how far he could go before he was stopped. However, examination of her first five issues shows a very consistent portrayal, and no sources have come forward to verify this rumor, so it has been effectively debunked.
Weaksauce Weakness: The aforementioned "diet soda" allergy to explain her attitude in the Giffen/DeMatteis Justice League Europe issues after they left the series, and her vulnerability to "raw, natural, unprocessed materials".
What Measure IsC-List Fodder: The Blue Snowman is killed soon after Vartox's arrival as a direct result of his attempts to "woo" Power Girl, and PG is quite perturbed at this (Even if she was a villain). However, in the next issue she has completely forgotten about the entire incident, and chats happily with Vartox without mentioning Blue Snowman at all.
Who Writes This Crap?!: She does not say the actual line, but Power Girl simply can not believe the story of Vartox and the infertility bomb that requires him to find a mate to save his planet. Power Girl is stifling laughter by the time he gets to the part about the "pregno-ray".
The Worf Effect: Lampshaded in her own series "why, oh why do I keep getting my ass kicked?!"