S1E18 - Michael appeared in the school play The Trial of Captain Hook. Later in the episode Fakin’ It from season 3, Lucille refers to Buster as “Captain Hook.”
S1E20 - “This party is going to be off the hook.”
S2E1 - When Lucille is watching the news, you can hear John Beard mentioning a surprise seal attack and then saying “meet one surprised bather, coming up.” The camera immediately moves to show Buster.
S2E3 - Buster arrives to Lupe’s house, sees the hand chair, and says “wow, i never thought I’d miss a hand so much.”
S2E6 -Buster is playing the claw machine and gets a toy seal. Later when he’s returning home, the narrator mentions that “Buster had gotten hooked playing” that game.
S2E11 - Lucille, Oscar and Buster and in the beach, and when they’re talking, the seal is seen in the background. Later, George Sr. says about Buster “what if i never get a chance to reach out and touch that hand of his again?” And of course, the bench that shows “arm off.”
S2E12 - When George Sr is at the car dealership, if you take a look at the inflatable doll/man in the back, you can see that it’s missing an arm. Also, when Gob is releasing the seal back into the wild, he says “you’re not going to be hand-fed anymore.”