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!
In "Bracelet of Power", a fly randomly lands on Mumm-Ra's nose while he's giving a monologue. He angrily flicks it away and rants that it will pay for disturbing him.
Then it gives him the idea to turn into a fly and sneak inside Cat's Lair...and his fly form has bugged-out red eyes and is wrapped in bandages.
Vultureman just wouldn't stop his tirade about how the Lunatacs should have listened to his plan to an aggravated Luna, and continues to mouth off when grabbed by Amok and thrown out of Sky Tomb...from the top floor
(after a loud THUD!)
Vultureman: If the world were full of vulturemen; we wouldn't have these kind of problems.