Creatures that look like 3-year-old children wearing penguin hoods and outfits. Because they ransacked city supermarkets and ate crops from fields, they were designated as Special Vermin by city ordinance. Originally unique to Fujiko City, they were once everywhere, but now they are rarely seen except as trained pets in the city or occasionally in the mountains. However, they can still be found in aquariums, zoos, and circuses. Shows where they perform extreme stunts and receive extreme punishments in front of the audience if they fail are quite popular. Even if the news reports a wild Gugu-Gaga Penguin appearing in the city, people react with the same indifference as hearing about a forest fire in a distant country. They speak in sounds like "Gugu-gaga" or "Gugaga~".

A mutation among Gugu-Gaga Penguins. Instead of a penguin suit, they wear a frog suit. They are rare, occurring in only 1 out of every 2,000 Gugu-Gaga Penguin eggs. Because their intelligence is higher than that of the penguin variety, they do not raid fields or steal; instead, they perform tricks or work to receive food from humans. They are often seen working or performing in the city.

A mutation of the Gugu-Gaga Penguin. Instead of a penguin suit, they wear a shark suit. They occur in 1 out of every 2,000 eggs. They are even more ferocious than the penguin type, but possess high intelligence. Recently, specimens trained by the police have been seen working as "Police Gugu-Gaga Sharks" (similar to police dogs) to dispose of wild Gugu-Gaga Penguins.