After a disastrous accident at an oil-drilling operation, businessman Simon Stagg tries to sell the oil company on his "Metamorpho" mutagen, which can turn an ordinary worker into a being capable of withstanding all manner of harsh conditions. After they rebuff him he orders his henchman Java to transport a briefcase full of the stuff on a train, which happens to be carrying another Stagg employee, Rex Mason.
After the mutagen is accidentally spilled the train derails, and is saved only by the intervention of Green Lantern. John Stewart recognizes Mason from his days as a Marine, and learns that he's become wealthy working for Stagg while also becoming secretly engaged to Stagg's daughter, Sapphire. After Batman detects the mutagen, however, Green Lantern questions Mason about what the company was up to.
Mason evades the questions, but then confronts Stagg on his own. When Stagg evades him too, he accepts a job offer with another company in Chicago and announces he's taking Sapphire with him. Stagg pretends to accept this, but then plots to use Mason as his guinea pig for the mutagen.
Once exposed, Mason becomes Metamorpho, a multicolored being able to transform himself into virtually any substance at will. When he wakes up and discovers his condition he flees his hospital bed, unintentionally causing an auto accident. Green Lantern promises Sapphire he'll find Mason, earning himself a thank-you kiss.
When Mason eventually confronts Stagg about what he did to him, Stagg distracts him by showing him pictures of Sapphire kissing Green Lantern, which sends Mason into a fight with nearly the whole Justice League. Eventually he escapes and confronts Sapphire, who points out to him that it was her father who showed him the pictures, and Mason realizes he's been manipulated.
Stagg, meanwhile, has brought another batch of the mutagen and is using a virtual-reality machine to work on it when Mason shows up and smashes the machinery. This causes the mutagen to escape and take a monstrous form, which seems to have absorbed some of Stagg's mind. The "synthoid" storms through the city and captures Sapphire, impervious to anything the Justice League tries to throw at it. Eventually Batman figures out a polymer that can neutralize the creature, but with no time to synthesize it Mason decides to convert himself into the polymer and throw himself into the creature.
The synthoid explodes and at first it seems Mason is dead, but then the remnants of material re-form into him.
Tropes:
- Adaptational Job Change: While in the comics before becoming Metamorpho, Mason was an archeologist, in the show he is a former marine turned businessman.
- Adaptive Ability: Implied. At least initially: Stagg's selling point of the "Metamorpho" mutagen is that the worker will adapt to the harshest of environments. While Metamorpho takes on Superman, it is completely one-sided in Superman's favor, until Metamorpho unknowingly turns his arm to kryptonite, and grabs him. Later J'onn tries to restrain him and he simply ignites himself. It's both noting that afterwards Metamorpho has control over his powers and has to stop the "synthoid" by willingly transforming into a polyymer that can neutralize it.
- Bait-and-Switch: At the end of the episode, it seems like the synthoid is reforming as the Justice League gets to fight it again, then it turns out what was really reforming was Metamorpho himself.
- Beast and Beauty: Despite Simon's hope that Rex's transformation would scare his daughter away, Metamorpho's appearance and abilities do nothing to deter Sapphire's love for him.
- Blob Monster: The synthoid. As stated by Superman when he attempted to hit it "It's like punching dough!".
- Corrupt Corporate Executive: Simon Stagg, who will clearly use any means necessary to advance his business.
- Crazy Jealous Guy: Mason totally flips his lid when he thinks Sapphire is cheating with John Stewart, though the other things happening to him are surely contributing to the crazy part. Also Simon Stagg; see Incest Subtext.
- Create Your Own Hero: After Mason is turned into Metamorpho by Stagg, he does what he can to keep anyone else from going through what happened to him.
- Dramatic Irony:
- Green Lantern wonders what it would've been like to be a rich executive with lots of perks, while Rex would've loved to be a superhero. They're unaware that a certain pointy-eared member of the League happens to be both.
- During the Final Battle with the synthoid, Sapphire initially believed the monster was Rex. Upon seeing Rex, she realized that the synthoid actually had her father's mind.
- Dumb Muscle: Java, a very Top-Heavy Guy, isn't the sharpest knife in the drawer.
- Foreshadowing: When Mason presses Stagg about the company's involvement with the earlier train accident, Stagg warns him to leave it alone, insinuating "I made you, and I can unmake you just as easily..." In a sinister way, this lets the audience know Stagg won't be above "unmaking" Mason into Metamorpho, a threat which he makes good on when he learns he's going out with Sapphire.
- Grass is Greener: Seeing how good Rex has it both professionally and personally, John starts wondering if he should've turned down being a Green Lantern and followed Rex's path. After learning that Rex looked up to him and would've loved to be a superhero instead of a well-to-do executive, John lampshades the trope.
- He Knows Too Much: Apart from trying to stop him for taking Sapphire, Stagg used Rex as the guinea pig for his mutagen because he was getting nosy about the project.
- Here We Go Again!: When League sees what they think is the synthoid reconstituting itself, Hawkgirl says "Here we go" as the League prepares to fight again. Turns out, it's Rex who's regenerating.
- Heroic Sacrifice: Rex Mason believes he'll probably die from throwing himself into the synthoid, but it turns out he's Not Quite Dead.
- Homage: The entire final sequence with the synthoid is an homage to King Kong, as the creature stomps through the city, snatches a pretty blonde and climbs up a building that looks suspiciously like the Empire State Building. Lampshaded by Mason, who remarks, "What I wouldn't give for a couple of biplanes right about now."
- I Am a Monster: Mason's initial reaction to his transformation.
- I'm Not Doing That Again: After turning himself into a chemical that causes the synthoid to blow up, Rex manages to reconstitute himself, saying this when he does.
- Incest Subtext: Simon Stagg's feelings towards his daughter seem awfully boyfriend-like, which explains why he can't stand the thought of her dating anyone. When we first see him visiting her apartment he brings flowers and primps himself as if he were going on a date. He then tries sending Rex after Green Lantern just because his daughter non-romantically kissed him, taking photos of the situation out of context. And later, of course, he plays King Kong to her Ann Darrow.
- Kill It with Ice: Java temporarily disables Metamorpho by freezing him; it's unclear whether this is a moment of unusual cleverness or just dumb luck that he stumbled on something that worked.
- Ladykiller in Love: Despite Mason's devotion to Sapphire unto death, in his introductory scene he's brazenly flirting with the stewardess on the train. (For that matter, Sapphire is pretty brazenly flirting with John later.)
- Let's You and Him Fight: Stagg tricks Mason into believing that John and Sapphire were having an affair to get him to attack John (and eventually fight the rest of the league) in order to get video footage of what the Metamorpho mutagen was capable of.
- Mirror Reveal: After falling prey to the accident Stagg staged for him, Mason wakes up in the hospital. From his viewpoint, Sapphire rushes into his room, only to faint at the sight of him. He doesn't realize the drastic extent the accident changed his appearance until he walks over to the mirror in his room...
- Modesty Towel: When Green Lantern first meets Sapphire, she's just out of the shower and wearing nothing but a towel.
- Mutual Envy: When John sees how happy and successful Mason is, he starts to wonder if becoming Green Lantern was the right career choice after all. Later, however, Sapphire tells him that Rex had always wanted to be like him.
- Mythology Gag:
- The synthoid bears a certain resemblance to Chemo.
- A man survives a train accident that becomes his superhero origin. This references the origin of the other Green Lantern Alan Scott.
- Nice Job Breaking It, Hero: Rex smashed Stagg's machine in an attempt to destroy the mutagen so he couldn't do to anyone else what he did to him. Unfortunately, this results in a Freak Lab Accident that causes the mutagen to come to life.
- Not Quite Dead: When remnants from the synthoid explosion begin to gather together, while a moan of "Sapphire" is coming from a face within it, the League initially assumes the synthoid is still alive. Luckily though, it's Rex instead.
- Oh, Crap!: Rex has this reaction when he realizes the synthoid has part of Stagg's mind, and as such, is after Sapphire.
- Police Are Useless: When Metamorpho encounters a few police officers, they immediately try to shoot at him due to his monstrous appearance, even though he is clearly non-hostile and calling for help.
- Poor Communication Kills: Stagg attempts this by showing Rex pictures of Sapphire kissing Green Lantern out of context to get him off his trail. After picking a fight with the Justice League, he then confronts Sapphire about it. She reassures him of her her love, which helps him realize the truth. He then rushes off to find Stagg without telling Sapphire. Once he finds Green Lantern he explains and warns that they need to stop the synthoid.
- Pulling Themselves Together: How Rex recovers after he destroys the synthoid.
- Shout-Out:
- When the train starts to derail, Mason quotes (or rather
misquotes) Bette Davis' famous line from All About Eve: "Fasten your seatbelts, it's going to be a bumpy ride!" - Also, at one point Mason calls Java Flintstone. In the comics, in fact, Java is an unfrozen Neanderthal, though the show doesn't explain this.
- When the train starts to derail, Mason quotes (or rather
- Small Role, Big Impact: The train attendant who took the briefcase with mutagen samples inside it from Java. If he hadn’t taken the briefcase, the train wouldn’t have crashed and causing the events of the episode, including Mason becoming Metamorpho, to unfold.
- Super Hero Origin: This episode is one for Metamorpho, as far as the DCAU is concerned.
- Voluntary Shapeshifting: Mason gets quite good at this remarkably quickly.
- What the Hell, Hero?: Sapphire calls out Rex for believing that John would betray him and that she would two-time Rex.
- You Have Outlived Your Usefulness: When Java asks Stagg how he's going to get Mason to work for the oil company, Stagg replies that Mason was just the prototype and doesn't need him anymore now that the Metamorpho mutagen has been successfully tested. It's at that moment that Rex, in water form, is oozing out of the nearby fountain.
