Later in the Batcave, Terry and Bruce watch a newscast, where Dr. Cuvier, head of the Chimera Institute and a splicer himself, insists splicing is "safe, reversible, and more importantly, utterly beautiful." Bruce fears something bad will come of this. And knowing from his experience of people trying to combine animal and human DNA go horribly wrong, he has every right to be. Next morning, Terry's brother Matt, wearing a wolf costume, scares him out of bed. As Terry chases him out of his room, Matt asks their mother if he can be spliced; Mary says no. Terry jokingly refers to Mary's tattoo from her "wild teen years" to which she says is different from "having antlers stuck on your head." Matt then says Terry is already a donkey and Terry angrily tells him he is lucky Terry is late for school.
On a vertical train, a newscast shows DA Sam Young announcing his plan to outlaw splicing completely because it increases aggressive behavior. Just then, Ramrod, a teenager spliced with ram DNA, slams the screen. He and King Snake, another splicer, cause trouble, saying splicing is the future, but Terry fights them off, earning the applause of bystanders.
Terry takes Dana to the Chimera Institute to investigate, and sees Ramrod and King Snake demand to speak with Dr. Cuvier. In his lab, Cuvier decides to have Young killed. Batman watches, but Tigress smells him and they capture him and Cuvier injects him with a special serum prepared just for him. When he escapes, he feels strange as Cuvier attacks him with his claws. He flies off to save Young.
At Sam's house, Barbara tells him he should relax, but he is determined to put Cuvier out of business. Suddenly, Ramrod, King Snake, and Tigress break in and attack. Batman arrives, violently beats the splicers and starts foaming at the mouth. Losing control, he rushes back to the Batcave. Barbara calls up Bruce to warn him of his condition, but Terry arrives, now in the form of a Man-Bat. In the struggle, Bruce manages to dart him with an antidote. Terry wakes up to a growling Ace and learns Cuvier spliced him with an overdose of vampire bat serum and that Young survived. The authorities are now after Cuvier, who has gone into hiding. Bruce notices one of Cuvier's claws on Terry. Using the claw's scent, Batman has Ace track Cuvier to Carmine's Taxidermy Studio.
Tigress smells Batman again and the thugs attack him. As Batman fights them off, Cuvier injects himself with various DNA doses. Batman manages to subdue and cure his attackers before heading for Cuvier. Using several animal serums, Cuvier has now mutated into a "true chimera" and proves a powerful foe. Batman injects him with several more DNA tubes, and Dr. Cuvier mutates into a giant creature that no longer resembles any living being. The creature captures Batman and nearly eats him, but Ace breaks in and attacks. The creature grabs Ace, but Batman saves him. The creature hits a power cable and ignites some gasoline. Batman and Ace escape and Cuvier likely dies in the explosion.
Later, Barbara thanks Terry for his help but advises him that the costumed life isn't worth it and has few rewards. Terry replies that "sometimes the small rewards are the best ones."
Tropes:
- Accent Upon The Wrong Syllable: The word chimera is pronounced as "shi-mera" though the technical pronunciation is actually "kai-mera." While the name for the splicing company may have been called "shi-mera" for fashionable preferences, Cuvier calls himself an actual chimera using the "shi" substitute.
- All There in the Script: The names of the three splicers (Ramrod, King Cobra, and Tigress) working for Dr. Cuvier are only given in the credits.
- And I Must Scream: Terry after he's been spliced into a Man-Bat, losing control over his body and getting animalistic until Bruce injected him with a cure.
- And There Was Much Rejoicing: Terry effortlessly making short work of two Splicers (after the pair boasted their superiority) caused some nearby patrons to cheer.
- Animal Eyes: Provides the trope picture from when Chelsea is revealed to have literal cat-eyes due to undergoing a splicer treatment.
- Bad Boss: Cuvier takes out his rage on Ramrod for failing to kill DA Young and leaving a witness in the attempt by savagely beating him.
- Bat People: Terry is spliced with a vampire bat serum, which turns him into a Man-Bat.
- Beast Man: Invokes the gene-splicing arm of this trope, oddly enough as a popular fad among teens ranging from Animal Eyes and noticeable horns, scales, fangs all the way to a humanoid chimera and repulsive mass of mixed-up flesh.
- Being Good Sucks: Downplayed. Barbara tries to warn Terry that being Batman isn't guaranteed to be worthwhile, as the stakes can be high and the rewards are small. But in light of Ace having bonded with him during the climatic fight, Terry voices that the small rewards are best.
- Bio-Augmentation: The episode deals with Terry fighting a group of teenagers who were spliced with animal DNA to take on certain animal traits. Other splicers are seen throughout the series.
- Body Horror: Terry involuntarily becomes a Man-Bat until he gets better. However, the really bad part is when, after splicing becomes illegal since it makes people more aggressive, Batman goes to confront Cuvier, who then turns himself into some weird hawk-tiger-snake thing and after knocking away Terry's gun filled with the mutagen cure, Terry starts sticking Cuvier with multiple syringes. Cuvier then transforms into a disgusting creature that is even today one of the most disturbing things ever put into a kid's show rivaled only by certain shonen, if not seinen anime series.
- Bond Villain Stupidity: Cuvier, rather than just killing Batman when he has the chance, instead decides to "splice" him and then try to kill him. Similarly, when Batman stops Ramrod, Tigress, and King Cobra from killing DA Young and beats them senseless, they leave, believing that the "psycho bat" will finish the job for them; instead, Terry manages to Resist the Beast long enough to get back to Bruce and get help.
- Drugs Are Bad: The episode primarily revolved around a body-modification moral, the genetic splicing served as a metaphor for cosmetic surgery, tattoos and piercings, but the process was addictive, mind-altering and administered through injections.
- Early-Bird Cameo: This episode marks the first appearance of Max Gibson, though she's not properly introduced until later episodes.
- Eldritch Transformation: Cuvier's final shape is...definitely not a kid-friendly case.
- Emerging from the Shadows: After being spliced by Cuvier and saving Barbara and DA Young, Terry goes back to the Batcave. First, we see a massive silhouette of Batman...and then Terry throws his mask at Bruce's feet and comes into the light, revealing he's become a man-bat.Terry: Bruce! Help...me!
- Family-Unfriendly Death: The episode ended with Batman injecting Cuvier with so much animal DNA that he mutated into a gigantic blob-crab-monster. It's not what kills him (what did him in was Terry stabbing him with his own stinger-like tail), but his thrashing around does end up blowing the place.
- Fighting from the Inside: Even after he was spliced, Batman manages to rescue the District Attorney from Cuvier's goons. It was after he fought them off that he started losing control.
- Fire-Forged Friends: This is where Ace starts treating Terry like his second owner, after the two fight Cuvier together.
- Former Teen Rebel: Mary McGinnis, according to Terry.
- Half-Human Hybrid: The Splicers, who got that way thanks to LEGO Genetics.
- I'm a Humanitarian: Cuvier tries to eat Terry after his overdose. Though it's likely that Cuvier doesn't qualify as human anymore.
- I Just Want to Be Special: Implied with the splicers, what with their harassment of everyday citizens, and called them "norms" derisively, to Ramrod's protest when Batman cures them that "[he's] not going back to being a nobody."
- LEGO Genetics: The Splicers have had their DNA spliced with different animal DNA, turning them into Half Human Hybrids. Terry is turned into a literal Bat-Man (a la the Man-Bat) at one point, but it is easily reversible. Splicing is made illegal, but at first was perfectly legal and akin to body piercing and tattooing.
- No Transhumanism Allowed: Splicing is highly controversial in-universe, and by the end is outright made illegal.
- The Nose Knows: Terry finds Cuvier by having Ace get his scent with the claw that was torn off in the fight.
- Parental Hypocrisy: Terry briefly calls his mom out by mentioning her tattoo after she speaks negatively of splicing. (And he may have a point there; if it had been only a fad, it would have been far less permanent than body art.)
- Phlebotinum Overdose: Terry has Cuvier overdose on his splicing injections.
- Power-Upgrading Deformation: The splicers used genetic engineering to become Half Human Hybrids, which generally while animalistic weren't ugly. When their boss fights Terry, he takes a boatload of them and goes One-Winged Angel...until Terry gives him a second round of drugs which pushes him into Clipped-Wing Angel.
- Pun: After Dr. Cuvier turns into a One-Winged Angel mopping the floor with Batman:Dr. Cuvier: Now you face a true chimera! You bring out the beast in me!
- Punctuated! For! Emphasis!:Batman: DON'T. TOUCH. MY. DOG.
- Resist the Beast: Cuvier splices Batman with vampire bat DNA, after which Batman escapes and goes to DA Young's house to save him. As he begins to transform, he brutally attacks the thugs and drives them off before advancing on Barbara, snapping out of it, and escaping. By the time he makes it back to Bruce, he's become a giant Man-Bat and has just enough self-control left to beg Bruce for help before he snaps.
- Shout-Out: The scene where Cuvier starts mutating after Terry injects him with various animal DNA, is shot almost exactly like Tetsuo’s mutation in AKIRA.
- Silver Fox: Ramrod briefly hits on Barbara Gordon.
- You're Insane!: Batman tells Cuvier this.Batman: Have you considered checking into Arkham for a little R&R, doc? Because, quite frankly, you're nuts.
