Kick It Up A Notch and its reprise both merit this.
Taz ripping Up's mustache off and sticking it on her own face.
"Now take a walk off my knife!"
"Calculus was TOUGH!"
All the puppets, but particularly the enormous Pincer puppet. Especially when you consider that Dylan Saunders has to hold his arms up for for long periods of time while singing and moving the mouth flaps in unison with his voice.
Up making the Mosquito Brothers violently explode by increasing his heartrate. Holy crap.
Joey's delivery of the Starship Ranger motto just makes you wanna punch the air and say "F*** yeah you are!"
Bug: You're right! I am a Starship Ranger, and I'M HERE TO GET THE GODDAMN JOB DONE!!!
"Okay, idiotas. Say something nice, or I will Kill you.
Bug's Heroic Sacrifice. He gets better, but it's still awesome. Doubles as a CMOH.
He may be the villain, but Junior's speech to Bug before he goes to shoot the overqueen.
JuniorWe have a saying where I come from too. "God save the queen."
Bug: Oh, cool.
Junior: Luckily for me, God is dead. When you see him in hell, tell him Junior sent you
Bugette's sacrifice, taking a shot meant for Bug. Then her larvae hatch, and as Bug points out to Junior, they go after the first mammalian source of nourishment they can find...