Negaduck starts a crime wave while disguised as Darkwing, turning the city against him. The situation gets worse when Dr. Sarah Bellum hits Darkwing with a disguise ray, causing him to turn into whoever he's looking at.
This episode contains examples of the following tropes:
- Bait-and-Switch: While they're driving to S.H.U.S.H. headquarters, Darkwing swerves the miss a dog and crashes the Ratcatcher. Launchpad and Gosalyn get up and see Darkwing's hat on a dog. They run off after "him"...and as soon as they're gone, the real Darkwing climbs out of the bushes.
- Continuity Nod: Darkwing's inability to fly his own plane comes up again when he takes the Thunderquack while transformed into Launchpad and reverts to himself midflight. He apparently crashed it quite badly.
- Gone Horribly Right: Darkwing looks at a mug shot of Negaduck so that he'll turn into him and know what his next move will be. The problem is that Negaduck has no fondness for either Gosalyn or Launchpad, and transformed into him, Darkwing no longer has any scruples about threatening them.
- Evil vs. Evil: At one point, Negaduck and Darkwing-as-Negaduck have a quarrel over which of them is the real deal.
- Here We Go Again!: After Darkwing has caught Negaduck and turned himself back to normal, he trips and accidentally triggers the ray, turning almost everyone at the scene into a duplicate of himself. This culminates in the episode having No Ending.Everyone: Let's get dangerous!
- Hoist by His Own Petard: Negaduck (disguised as Darkwing) tries to kidnap Darkwing after he turns into a baby. Unluckily for him, his scheme to frame Darkwing causes the bystanders gang up and beat the tar out of him.
- Impersonating the Evil Twin: An odd variation in that Darkwing actually turns himself into Negaduck in order to find the real Negaduck's hideout.
- Involuntary Shapeshifting: Darkwing is unable to control the transformations and ends up changing every time he looks at someone.
- The Last of These Is Not Like the Others: After crashing the Thunderquack, Darkwing mentions that not only had he sustained massive internal injuries, but that he was then chased by the army, the navy and a girl scout troop with pinking shears.
- Masquerading As the Unseen: While it helps that Negaduck is also Darkwing's alternate self, part of the reason he can frame him might be that few people in St. Canard know who Darkwing is.
- Morphic Resonance: Darkwing and Negaduck keep their beaks whenever they transform, and Darkwing also keeps his own height as the maximum height he can achieve.
- Punny Title: The title is a pun on "the sky's the limit."
- Shout-Out: Negaduck and Darkwing-as-Negaduck threatening each other with an escalating arms race is inspired from Rabbit of Seville.
- Terms of Endangerment: Darkwing, after transforming himself into Negaduck, calls Gosalyn "shnookums" while chasing her and Launchpad with a burner.
- The Mind Is a Plaything of the Body: Darkwing's mind changes with every new form he assumes. This causes trouble when he takes the Thunderquack out as Launchpad and then changes back midflight, and again when he turns himself into Negaduck and gains his destructive tendencies.
- To Know Him, I Must Become Him: Darkwing tries this to find his Evil Twin Negaduck. Problem is, he's also suffering from that week's Applied Phlebotinum accident. He actually becomes Negaduck. Gosalyn and Launchpad easily find him by following the trail of destruction. Then again, he did find Negaduck — and then accused him of being a fake.
- Vocal Evolution: Darkwing-as-Negaduck's voice is a dead ringer for the real Negaduck's in his first scene. However, when he confronts the real Negaduck, his voice is now closer to his own voice imitating Negaduck. More than likely, it was to help differentiate the two since they looked exactly alike.