That’s in the episode where bender flushes nibbler down the toilet, Fry is talking about visiting the sewers to get him back and Zoidberg’s reply you quoted is about the sewer mutants.
Isn’t Melvarrr spelt with three "r"s ?
My personal favourites.
Professor: “Good news everyone, The university is bringing me up on disciplinary charges. Wait. That’s not good news at all”
Gypsy: “Yes I am your friend. Bonder.” “I am fine. Give the gypsy ten dollars”
Zoidberg: “And while you’re under the knife you could get an ink sack to evade your enemies”
Professor: “That’s the dumbest thing I’ve ever heard!” <Gets covered in ink>
Kiff, I have made it with a woman! Inform the men.
Zapp: I find the most erotic part of the woman to be the boobies.
Zapp: Leela. L-E-E-L-A LEEEEELA
Zapp: Have the boy lay out my formal shorts.
Kiff: The boy, sir?
Zapp: YOU! You lay out my formal shorts!
Morbo to his wife (under his breath): I will DESTROY you.
Bender: Like when you burn down a bar for the insurance money!
God: Yes, if you make it look like an electrical thing.
Bender (singing): Using a word for something other than it’s literal intention. Now THAT is irony!
Zoidberg: The music is bad and you should FEEL bad!
And my all-time favorite quote, but only because I didn’t get it until I became a really big geek:
Melllvar: I thank you, Fry. You know, you and I are of a kind. In a different reality I could have called you “friend”.
Fry: Episode 10, Balance of Terror.
Melllvar: More like episode nine, loser! In your face! Victory is mine!
Zapp Branigan(on how he defeated a horde of Killbots): You see, the killbots have a preset kill limit. Knowing their weakness, I sent wave after wave of my own men at them until they reached their limit and shut down. Bender(sniffing): A grim day for robotkind. Ah well, we can always build more killbots!