During the scene at the Blimpo Store from Robo-Mama, the second girl Johnny sees and thinks "she's the one", is Melinda, the same black girl who was introduced in the episode Witless (and later named in the episode Candidate Johnny), and has had cameos in other episodes as well.
Originally, the episode 20,000 Leagues Under My Head was supposed to be called Voyage of the Darned.
Debbie Nemo, the captain from the episode 20,000 Leagues Over My Head is drawn to resemble her voice, actor Kath Soucie.
In the episode 20,000 Leagues Over My Head, when Johnny is underwater his swim trunks turn blue. In all other scenes when he has them on they are red.
Johnny: Mama, couldn't I just stay here on the sidewalk?
Robo-Mama: And fall down and swallow your tongue? Nothing doing.
Johnny: Well, what took you so long?
Debbie Nemo: Captain's log: Johnny isn't working out as I plan. On 4/9 I assigned him to the task of salvaging sponges from a nearby reef. Instead, he used them to lather up with some industrial soap poisoning the entire area.
(On the Clam League 9000 show):
Person #1: Chincoo can spit acid and it can tap dance!
Person #2: Well, Macanaw can shoot fire from its tongue and has memorized the songs of ten birds!
Danger, Johnny Bravo! Danger!
The Robo-Mama seen in the segment with the same title uses this phrase to warn Johnny of a potential hussy while in the supermarket. The phrase is an allusion to the "Danger, Will Robinson!" catchphrase, popularized by the TV series Lost in Space (CBS; 1965-1968). The saying became the catchphrase of the Robot - "portrayed" by the infamous Robby the Robot model, worn by actor Bob May, with actor Dick Tufeld providing the voice. The phrase was used in only one episode of the show when the robot, acting as a surrogate guardian, tried to warn young Will Robinson (played by actor Bill Mumy) of an impending threat.
Despite being present in only one episode, the phrase became somewhat of a running gag or meme in recent years, being used in various other projects, including Sabrina the Teenage With, The Simpsons, How I Met Your Mother, as well as this episode of Johnny Bravo.
The Clam League 9000 show Johnny is watching during 20,000 Leagues Above My Head borrows several elements from different other anime.
The most obvious one is that they spoof Pokemon. While on Pokemon the monsters came out of "Pokeballs", here they come out of clams.
Also, the two humans featured on the show resemble Goku and Vegeta from Dragonball Z.