From the Wikipedia entry for 'Afternoon Delight' (2x06):
Buster sees a plush seal in the skill crane, wearing a shirt that says "Good Luck". Buster then points to the seal and says, "That could be good for Army," implying that a seal with clothing will help him get out of the army, something that later happens in "Hand to God". The Narrator later says that Buster had "gotten hooked playing the skill crane," placing particular emphasis on the word "hooked", all the while the camera is zoomed in on Buster's hand that is operating the claw. The hand he's using is his left hand, which is the one he loses and for which he gets a prosthetic hook.
'Out on a Limb' (2x11):
Buster is on his way to the Army when he decides to finally go swimming in the ocean, where a loose seal bites off his hand, after he misinterprets a warning from a coastguard about a "loose seal" with a response about his not caring about Lucille.
'Hand to God' (2x12):
The next day, Buster returns from the hospital, fitted with a metal hook prosthetic, to find the family gathered in Lucille's penthouse under a banner which reads "Welcome Home, Buster!" (the "You're killing me, Buster" banner strategically covered up). Buster says, "Let's give me a big hand!" and everyone forces awkward laughter. Gob arrives at the party ignorant of Buster's accident, and is scared by Buster's hook. When Buster says his hand was bitten off by a seal wearing a yellow bow-tie, Tobias attributes that statement to the "playful mutterings of the shock victim" because a seal would never attack a human. "Unless, of course, it had acquired a taste for mammal blood." Flashback to Gob performing a magic show with a seal wearing a yellow bow-tie, when a cat jumps into the chest where the seal is hidden. Cut to another flashback in which Gob releases the seal into the ocean saying, "You're not going to be hand-fed anymore.
Of course, how in the world would you catch the foreshadowing on TV? You gotta ask: why are they dropping cryptic references to the 'loose seal' accident five episodes in advance?
Well. Because they can.
None of this loose seal/Lucille/claw/limb/hand stuff is actually funny the way, say, Tobias's analyst/therapist business card is. But it's a big part of the attraction of Arrested Development. The casting of Scott Baio as Henry Winkler's replacement (on a show produced by Ron Howard) has the same sort of intellectual appeal: there's a nerdy audacity to the writers building these levels of metatextual and self-referential humour into the show, and catching references is one of TV fans' main pastimes in this data-driven (rather than knowledge-driven) consumption age.
What made Arrested Development a great show, rather than an 'interesting' one, is that for all its allusiveness and dense self-reference (some might say self-regard?), it was a strong example of a classically-structured sitcom as well. The characters were set up as sitcom types, and the elders' performances - in the roles of George, Oscar, Lucille, Lucille II, Stan Sitwell, Barry Zuckerkorn, etc. - were in a familiar sitcom style, however beautifully performed. (Jeffrey Tambor, in particular, brought a startling humanity and pathos to his work as George/Oscar, quickly outgrowing the broad material he was given in the early series.)
The point here is only that Arrested Development, like Seinfeld and The Simpsons, was a well-executed example of a familiar comedy type as well as a formal advance for the sitcom. Seinfeld's circular plotting and moral chilliness, The Simpsons's visual density and deep self-referentiality, and Arrested Development's pomo involution and formal ingenuity would all be forgotten were it not for their familiar comic modes - Lampoon-style WASP magazine-minicomedy in the cartoon's case, Borscht Belt stage theatrics for the thoroughly Jewish live-action shows. Arrested Development is the end of a developmental line that includes both the two earlier sitcoms and (crucially) The X-Files (which was both a self-referential funhouse and a bit of a genre catalogue) - but also a healthy dose of The Golden Girls.
In other words, your grandparents couldn't have loved Arrested Development the way you do, ya hip 21st-century white kid - too much rides on form and style - but the jokes themselves are old, old, old.