The octopuses are minor characters in The Backyardigans.
Octopuses appear on various The Backyardigans merchandise, despite never being shown in the series itself. They appear in books, on promotional art, and on a Backyardigans shirt sold by Koba Entertainment.
The octopuses have not appeared in any episodes of The Backyardigans, but they can be seen in the Deep-Sea Countdown book and on promotional art for Sea Deep in Adventure. An octopus is also included as part of Bobblin' Figure Packs Series 1.