After SpongeBob explains how great old people are, there's a live-action shot of an old guy in a captain's hat giving a thumbs-up. This is Don Newhouse, a parking lot security guard for Nickelodeon. He would later appear as a Nickelodeon security guard in the "Slime Day" segment of Slime Day/Boog Zapper (2012), and was the model for the "Old Kid" character in Invader ZIM (2001).
Mermaid Man and Barnacle Boy are voiced by
Ernest Borgnine and Tim Conway. In the 1960s, the two had starred together in the wartime comedy sitcom, McHale's Navy (1962), as Commander McHale and Ensign Parker. Funny enough, their roles have reversed here. In "McHale's Navy", Borgnine was more the straight man with Conway as his goofy sidekick, but on SpongeBob SquarePants (1999), Borgnine is goofy and senile, while Conway is grouchy and irritable.
In "Pickles" the song "Dancing the Hula" that played in the soundtrack was reversed during the scene where Mr. Krabs notices SpongeBob's house looking messy.
The receptionist at the nursing homes is reading a newspaper that says, "Global Ocean Warming" and "School drop out rates rise".