Written by: John Semper
The episode opens with the Chameleon, a master of disguise and international terrorist, attempting to escape Agent One and other agents of the Supreme Headquarters, International Espionage, Law-Enforcement Division, or S.H.I.E.L.D., resulting in where he hijacks a J3 helicopter and crashes it into a skyscraper, causing Spider-Man to rescue everyone involved, including the Chameleon, who quickly makes himself scarce once on the ground before anyone gets a good look at him.
Later, when Peter is attempting to ask Jameson to attend an upcoming treaty signing at the United Nations, the two of them find themselves being taken to S.H.I.E.L.D. headquarters, where Jameson meets with the head of S.H.I.E.L.D., Colonel Nick Fury, who's none too happy about a goof Jameson made in Fury's obituary, but then gets to business with explaining about the Chameleon and how he's been hunted by Fury's forces around the globe but has eluded capture every time thanks to his disguise belt. Fury has tracked the Chameleon to NYC under the belief that the Chameleon will ruin the treaty signing, resulting in war if he's not stopped. Jameson is holding a party for the VIPs and will have police, security, and FBI there, but Fury will also have undercover agents there as well, so if Jameson is worried about anyone being the Chameleon, all he has to do is press on a special lapel pin that Fury places on the collar of his suit, and Fury's undercover agents will respond in a heartbeat. Having said what he needed, Fury has Jameson and Peter taken back to the Daily Bugle, while when Peter, who had eavesdropped on Fury's conversation with Jameson, asks what happened, Jameson simply says its a matter of national security and nothing else.
At the Bugle, the Chameleon, disguised as Jameson, acquires several more disguises from the Bugle employee files, including Peter, Robbie, and Glory Grant, before using his disguise to slip past the real Glory and escape. However, when Peter talks about Robbie, suspecting Robbie could be the Chameleon, Jameson warns the undercover S.H.I.E.L.D. agents in the Bugle, and when Spider-Man intervenes when they catch the real Robbie, Fury sends his elite second-in-command, Agent One, to investigate. Once she sees Robbie is the real deal, she orders the agents to spread out to find the Chameleon, who disguises as Glory, only to be spotted by one of the undercover agents. When the Chameleon is caught on the stairwell by Spidey, she gasses him and escapes, forcing Spidey to avoid Agent One and the others when they come down the stairs in pursuit. Disguising himself as Peter, the Chameleon makes his escape out of the building, but not before being caught by Mary Jane, who asks Peter to come to her play performance that night. Kissing her to avoid the agents that come out of the elevator, the Chameleon makes his escape while Mary Jane thinks the kiss means he'll show up.
That night, the VIPs show up at Jameson's party, but Fury already has Agent One and her team in position, even having Agent One in formal attire to blend in, when they spot the Chameleon attempting to infiltrate the building. By the time Fury is sending agents to investigate, the Chameleon is caught by Spider-Man, but using a smoke grenade for cover, the Chameleon is able to disguise himself as Agent One and fool the other agents into thinking Spider-Man is the Chameleon while she escapes. With things getting out of hand, Fury decides to come down personally to evacuate the VIPs and orders Agent One to see to it until he arrives. Agent One orders her pilot to the roof to speak to Jameson and tell him of the situation.
Meanwhile, Mary Jane is doing her play, but notices that Peter never showed up, yet she still performs her best while glancing over at the empty seat where Peter should be, her anger silently rising by him being a no-show.
Back at the party, the Chameleon attempts a distraction by cutting off the gas feed to the kitchen, having them send a J3 maintenance worker down to investigate, allowing the Chameleon to knock him out and steal his identity, but before he can reach the VIPs while the gas is restored, Agent One beats him to it, letting Jameson know it's time to get the VIPs out of there.
On the roof, Fury is waiting for them, much to Agent One's surprise, until Spider-Man realizes Fury is the Chameleon as Fury's eye patch is on the wrong eye. When Spider-Man tries to intervene, the agents arrest him, but before Agent One can finish him off, the real Fury contacts her to ask for a sit-rep. His cover blown, the Chameleon attempts to flee in a S.H.I.E.L.D. gunship, but Agent One manages to cripple the helicopter and have it crash in the water. As she and other agents head down to make sure the Chameleon didn't escape, Spider-Man reveals how he knew it was the Chameleon from Fury's obituary picture to Jameson.
The day comes for the treaty signing at the United Nations, and Jameson and Peter are in attendance, with Peter carrying a camera with an extended lens so he can get a good shot, but just as he takes the shot, Spider-Man intervenes and throws off the shot, revealing the camera to be a weapon to assassinate the delegates, and Peter to be the Chameleon if Spider-Man is here. As Spider-Man and the Chameleon fight, Spidey manages to severely damage the Chameleon's disguise belt, causing him to change between all his disguises he used before collapsing unconscious to the ground, leaving him to be arrested by the authorities while Spidey escapes. As Spidey voices his disgust to his stone gargoyle friend at having saved the world, Colonel Fury appears to commend him for a job well done.
Back home, Peter answers the door to find a very angry Mary Jane there, who slaps him for not showing up for her performance (and for kissing her). Realizing this was the Chameleon's doing, Peter chases after Mary Jane to apologize and explain everything to her (or tries to).
Day of the Chameleon provides examples of:
- Big Damn Heroes: At the UN, Spider-Man foils the assassination at the last second.
- Bittersweet Ending: Spider-Man stops the Chameleon’s assassination attempt, Nick Fury even thanks him, but thanks to the Chameleon Mary Jane is furious at Peter for not showing up at her play.
- Chekhov's Gun: Nick Fury's obituary photo, where the negative was accidentally reversed. The Chameleon didn't know that when he copied it for a disguise, which allows Spider-Man to see through the attempt.
- Divide and Conquer: The Chameleon briefly transforms into Spider-Man to get the S.H.I.E.L.D agents to attack the real Spider-Man.
- Dramatic Irony:
- The Chameleon gave himself away to Spider-Man by disguising himself as Peter Parker, Spider-Man’s true identity.
- In the end, the Chameleon does score a victory against Spider-Man... by unknowingly mucking up his personal life.
- Forceful Kiss: As the authorities are getting close to him, Chameleon forces MJ into a kiss in order to blend in, which MJ thinks is simply "Peter" flirting.
- Hero of Another Story: Nick Fury both for being a war hero and running S.H.I.E.L.D..
- Mistaken Identity: Mostly Played for Laughs as hapless Bugle employees are tackled by S.H.I.E.L.D agents when mistaken for the Chameleon. Also at the end of the episode, Peter finds Mary Jane wrongfully furious with him after the Chameleon's impersonation of him.
- Never Found the Body: Defied after the Chameleon's helicopter crashes in the river. The assembled agents immediately begin a search to confirm whether or not he survived rather than leave it to chance.
- Not Quite Dead: To the wider world, Nick Fury is believed to be dead. Jonah is stunned to learn otherwise since he published an obituary for him years ago.
- Shapeshifter: The Chameleon's MO.
- Shapeshifter Swan Song: Happens after Spidey breaks the Chameleon's imaging device.
- Silent Antagonist: The Chameleon never speaks in his own voice, only through his disguises. Word of God is that this was intended for Rule of Creepy.
- Throw the Dog a Bone: Nick Fury congratulating Spider-Man for stopping the Chameleon.
