After ditching Army to play a claw game, Buster wins an arctic seal stuffed animal. Upon returning home he is shamed into lying to his mother. According to Buster, Army gives out seal stuffed animals for marksmanship. ("Afternoon Delight")
After his wife left to join Army, G.O.B. began using a seal with a yellow bow tie in his magic act. One show, a cat was locked into a trunk with the seal and the seal acquired the taste for mammal blood. Because of this, G.O.B. released the seal into the Pacific Ocean. Buster, waiting for a bus to take him to Army, decided to swim in the ocean as one last act of defiance against Lucille. While swimming, a pedestrian warned Buster of the "loose seal" before Buster's hand was bitten off by the seal. ("Out on a Limb")
After the seal bit his hand off, Buster was rushed to the hospital, where no one believed that a seal with a yellow bow tie really bit his hand off. Tobias mused that they were playful mutterings of a shock victim, and a seal would only attack if it acquired the taste for mammal blood. G.O.B. confessed to Michael they he used a seal with a yellow bow tie in his act. He then attempted to hunt for the seal using terminal cats as live bait, in order to remove the incriminating bow tie. He failed. ("Hand to God")
Buster suffered from night terrors when he awoke and saw his stuffed arctic seal in his bed. G.O.B. found out his wife was suing him $250,000 for the lost seal so he decided to get it (and Buster's Swatch that the seal swallowed) back. Barry discovered the seal had a tracker and it had been located. They followed the tracker to a dock and discovered that a shark had bitten the seal's flipper off. ("Motherboy XXX")
After Buster receives a medal from Army, Lucille jokes that it was because he was "food". Tobias notices Buster is extremely anxious about seals and attempts to help him overcome his fears. He wears Lucille's sealskin coat to teach Buster that's he not afraid of seals but of Lucille and he shouldn't even fear her. After picking Rita up in the family cabin, Buster knocks her unconscious because she's wearing a seal backpack. This act temporarily helps him overcome his fear. ("Forget-Me-Now")
Buster is afraid to go on the RMS Queen Mary for George's exoneration party due to his fear of seals. At the party, he wears life vests and sits in a life boat, but nevertheless he falls off and is confronted by a seal. ("Development Arrested")
From "Family Ties"
G.O.B. and his wife are about to "seal the deal" of their marriage when she remembers about an impending seal deal. ("Altar Egos") They finally "seal the deal" later, just before G.O.B. claims they never consummated the wedding. ("Motherboy XXX")
G.O.B.: Time to seal the deal.
G.O.B.'s wife: Oh, wait, what time is it? Oh, God, seal the deal. My seal deal. I got to get to Sea Land. I’m selling five of their sickest seals to a third world zoo.
G.O.B.: Did you say seals?
G.O.B.'s wife: Yes, I told you, like, four hours ago, I sell seals! God, you ever listen to what I say?From "Altar Egos"
G.O.B.'s wife: Unbelievable. The seal deal fell through. Three of the seals died on their way to Chad. How am I ever going to find a maritime lawyer?
G.O.B.: I’m sorry, did you say seals?
G.O.B.'s wife: Yes. I trade trained seals for a living. Do you ever listen?
From "Altar Egos"
John Beard: Are you living in one of Saddam’s many palaces? They may have been built by the same developer. And a seal attack. Meet one surprised bather, coming up.From "The One Where Michael Leaves"
From "Afternoon Delight"
G.O.B.: Yes, but it’s all coming back to me now. She was a seal dealer. She raised and sold seals to aquariums and marine parks, that sort of thing. Then she went off to fight her war and left me to look after them.
Michael: I’ve never known you to look after a seal.
G.O.B.: Turns out it’s a major hassle. Tried to include one in my act once. There is a reason you don’t typically see live seals in a magic show.From "Out on a Limb"
Narrator: ... and Buster is on his way when he decides to pursue a long-delayed rite of passage, ...
Person: Loose seal! Watch out for loose seal!
Buster: I don’t care about Lucille! She lies!
Narrator: ... and then a seal bites off his hand.From "Out on a Limb"
Buster: Actually, I’m relieved. I don’t have to go to Army because the seal with the bow tie attacked me. I feel like I’ve lost three pounds.From "Hand to God"
Michael: Buster went swimming in the ocean and according to him, a seal with a bow tie bit off his hand.
G.O.B.: Bow tie?
Tobias: It’s merely the playful mutterings of the shock victim. A seal would never prey on a human, unless, of course, it had acquired a taste for mammal blood.
Narrator: G.O.B. had recently dressed a seal in a bow tie and used him in a magic trick. When it failed, he released the seal into the ocean.
G.O.B.: You’re back in the real world. You’re not going to be hand-fed anymore!
- End flashback
G.O.B.: I mean, how the hell would a seal know how to tie a bow tie anyway? I can barely tie the yellow one that I wear in my act.
Buster: This one had a yellow bow tie!
G.O.B.: Really?From "Hand to God"
G.O.B.: I did this. I think that the seal with the yellow bow tie might be the one that I released into the sea after giving it the taste for mammal blood.
Michael: Okay, you’ve got a better case than Mom does.
G.O.B.: Still, I could hunt down that seal.
Michael: Well, they said if you retrieve Buster’s hand, they might be able to do a transplant.
G.O.B.: At the very least, I could remove that incriminating bow tie.From "Hand to God"
From "Hand to God"
G.O.B.: Anyway, remember that seal of hers that I released into the ocean? Bit off Buster’s hand?
G.O.B.: Her lawyers are claiming that the seal’s worth 250 grand. And that’s not even including Buster’s Swatch.From "Motherboy XXX"
Barry: All right, who’s ready to show their lawyer some love? The seal? Must have had a tracking device on it. Someone tracked it all the way to a dock in Dana Point.
Michael: You know if that hand is still intact inside the seal, Buster’s got a shot at a transplant.
G.O.B.: At the very least, we can get Buster’s Swatch back, right?From "Motherboy XXX"
Barry: Oh, oh, oh, I’m so sorry. False alarm. What they tracked down was a shark. And he must’ve bitten off the part of the seal with the tracking device on it. Left flipper.
Buster: So... the seal lost his hand, too.
G.O.B.: Yeah, poor guy’s probably out there without a flipper, swimming around in a circle, freaking out his whole family.From "Motherboy XXX"
Lucille: It’s probably because a seal bit off his hand. The army has taken to giving medals for being food.From "Forget-Me-Now"
Narrator: Buster had overcome his fear of seals. Unfortunately, he’d done so by knocking out Michael’s new girlfriend.From "Forget-Me-Now"
Lindsay: Yeah, but a 40-year-old woman has as much a chance of getting married as does of getting attacked by a shark.
Buster: (Shrieks.) Oh, I’m sorry. I thought you were going to say “seal.”
Lindsay: Or a seal.Buster: Oh, God!
From "Development Arrested"
I don't know where to put this but there's also the part when Gob is releasing the seal, and says "Time to get back in the real world! Not gonna be hand-fed any more!"