Air date: March 14, 2005 (FR), October 1, 2005 (US)
"An Enemy in Need" provides examples of:
- Aesop Amnesia: Once again, Knuckles allows himself to be fooled by Eggman's lies, and ends up actively fighting his friends in an effort to retrieve the Chaos Emerald and give it to him. The others even call him out on this, reminding him of all the other times Eggman lied to him and calling him out on being such a Gullible Lemming, while not incorrect.Cream: Dr. Eggman is always saying he'll abandon his evil ways, but he never does!
Amy: And yet every time, he somehow gets you to believe him. - Blackmail: Rouge starts blackmailing Bokkun about Cream.
- Cobweb Trampoline: Not exactly webbing, but during the planet's natives' celebration for getting their planet egg back, Sonic and the gang are heralded as heroes by bouncing on giant nets that act as trampolines.
- Continuity Nod: When Amy calls Knuckles out on letting himself fall for Eggman's latest lie, we're shown flashbacks to "Cracking Knuckles", "A Dastardly Deed" and "Eggman for President." Eggman lied to Knuckles 3 times and now he's lying to him a 4th time.
- Cross-Popping Veins: Knuckles gets several once Eggman lets it slip that he was lying to him yet again.
- Evilvs Evil: Soon after Knuckles realizes Eggman's lies, a Metarex foils his plans and sends him flying.
- Go Through Me: Sonic and Amy both tell Knuckles he'll have to go through them if he wants to give Eggman the Chaos Emerald. Knuckles is happy to oblige.
- Here We Go Again!: Sonic says this word for word after Knuckles claims that Eggman had changed his ways.
- Horrible Judge of Character: Knuckles towards Eggman, as per usual. The others flat-out call him out on falling for Eggman's latest claim that he'll reform if they give him the Chaos Emerald and remind him of all the other times he lied to him; even then, Knuckles adamantly refuses to even consider the possibility that Eggman is lying again and insists on giving him the Emerald and the benefit of the doubt until Decoe and Bocoe show up and Eggman himself lets it slip that Knuckles fell for it.
- I Told You So: After Eggman lets it slip that he lied to Knuckles once again, Sonic is quick to remind Knuckles that they did tell him as such, but it fell on deaf ears.Sonic: Hate to say "I told you so."
- Let's You and Him Fight: Sonic and Knuckles end up in a fight over whether or not to give Eggman the Chaos Emerald. Eggman tries to use it to his advantage to take it while they're distracted.
- Never Heard That One Before: When Knuckles tells the others to hand over the Chaos Emerald to Eggman, the doc having promised to change if they help him, the others respond with this, reminding Knuckles that Eggman tells him as such all the time and no matter what, Eggman will never change his ways and that he's lying to Knuckles all over again.
- Nice Job Fixing It, Villain: Had Bokkun not sent Decoe and Bocoe to help Eggman, Knuckles never would've realized that Eggman was lying to him again and would have given him the Chaos Emerald voluntarily.
- Obstructionist Pacifist: Cosmo is this, as she became dismayed to see Sonic and Knuckles fighting each other and tries to stop them, despite her friends's dismissal of it, saying that's how they solve their arguments.
- Oh, Crap!: Eggman had this reaction after he lets it slip that he lied to Knuckles once again.
- Pain to the Ass: Downplayed and only present in the Japanese dub's dialogue. While bouncing on trampolines during a celebration for getting the planet egg back, Amy complains that her butt hurts from all the bouncing. Later, Amy lifts the back of her dress up and shows her butt towards Cream, asking her if it looks bruised.
- Rousseau Was Right: Discussed. As Cosmo puts it, Knuckles is so easily tricked by Eggman all the time because he believes in honesty and that there's good in everyone. Knuckles theorizes that may be the reason himself. As Sonic points out, however, Knuckles is still "a sucker" for letting Eggman trick him all the time anyway. Good one, Sonic.
- Sadistic Choice: When he lets it slip that he was lying to Knuckles yet again, Eggman decides to dispense with the pleasantries entirely, capturing Cosmo with the Egg Mars and threatening to crush her unless Sonic and co. hand the Chaos Emerald over. His plan is derailed when the frog Metarex appears and takes it for itself.
- Save the Villain: When Amy catches Eggman in the act of trying to steal the Chaos Emerald and tries to pulverize him with the hammer, Knuckles, still believing his lies, immediately moves him out of the way, much to Amy's chagrin.
- Saying Too Much: When Decoe and Bocoe arrive in the Egg Mars mech, they remark Bokkun told them that nobody fell for his plan to steal the Chaos Emerald, which leads to Eggman slipping up and revealing that yes, he was lying to Knuckles yet again.Bocoe: He told us that nobody fell for your plan to steal the Chaos Emerald.
Eggman: I wouldn't go so far as to say nobody fell for it. Knuckles certainly did. [slaps a hand over his mouth] - Selective Obliviousness: Knuckles adamantly refuses to even consider the possibility that Eggman is lying to him again, even as his friends tell him as such point-blank and remind him of all the other times he tricked him. He only realizes the truth when Eggman himself lets it slip, and Sonic is quick to go on an "I told you so" routine. Everybody tried to tell him, but he didn't listen.
- Shameless Fanservice Girl: This occurs in the original japanese dub. When Cosmo gets nothing but white noise from everyone not doing anything to stop Sonic and Knuckles's fight, Amy at one point lifts the back of her dress up towards Cream and asks her if her butt looks bruisednote . Curiously, aside from it being a Call-Back to an earlier scene in the episode with Sonic and Co all being bounced on trampolines during a celebration, during said scene, Amy was holding her dress down so that no one could see under her dress.
- You Have GOT to Be Kidding Me!: Amy's word-for-word reaction when Knuckles stops her from hammering Eggman. Think for a second Knuckles, how many times has Eggman lied to you?
