Quite a lot of "The Heir up There", especially due to the Royal Tweetums' and Sylth Vester's dynamic mirroring that of the original Tweetie Bird and Sylvester.
Sylth Vester shows Danger Duck what happened to him after his head got stuck in a black hole by taking off his helmet. We don't see his face, but Duck's reactionsays it all.
Sylth Vester thinks he's averted the self-destruct of his ship when nothing happens after the computer says "one", only for the countdown to continue with "Zero. Bye-bye". You can guess Sylth Vester's reaction.
Danger Duck states that he doesn't even know how to spell "fear", which causes Lexi to remark that there are a lot of words he can't spell.
Danger Duck thinks he's in the clear when the Sagittarius Stomper starts targeting Tech, only for Tech to read in the threatening letter that the Stomper is still going to come for Duck.