When Lion-O faces off against Tashi in the episode "The Doomgaze."
Lion-O: She's... so beautiful...
Lion-O: I-In a kind of evil way, of course.
While it's technically not apart of the actual show, the infamous blooper reel certainly qualifies.
It introduced us to the word, Samoflange!
Lion-O: What the fuck is a Samoflange?
I liked Slithe's own unique version of the "No * * Sherlock" line from the episode "Return of the Thundercubs".
Vultureman: We're up side-down!
Slithe: Thank you Sherlock Holmes!>:[
I'll be the first to admit I'm not a Captain Bragg fan but, that crow sidekick of his cracks me up just about every time he talks. It's probably got a lot to do with the fact that I am a huge Groucho Marx fan!