Foster's Home For Imaginary Friends

When Goo is singing to torture Mac and Bloo, a remix of multiple Hillary Duff and Britney Spears songs are heard.

The way Goo rides on Coco's back seems to be a resemble of Mario riding on Yoshi's back from Super Mario World.

Bloo: I am no longer Bloonan the Barbarian! I am not the Blooinator! This is a play off the movie Terminator, right down to Bloo's accent as he says this.

When Eduardo imagines himself like baker, the style looks similar to Nintendo's video game character Kirby.

Goo: Princess Hillary Britney LollSpop star Goo's name seems to be a combination of Hillary Duff and Britney Spears, who are both pop stars

Eduardo: Alter ego Eduardo says that when he's not Eduardo, but "Ed Baker", it is an in-joke on the Emmy-winning storyboard editor for this series.

Bloo's two alternate identities (Bloonan the Blobarian and The Blooninator) are references to Conan the Barbarian and The Terminator, respectively. Coincidentally enough, both of these roles were played by Arnold Schwarzenegger.

When Wilt imagines himself as an evil villain, the associated drawing that appears looks somewhat like Optimus Prime from the Transformers franchise.

Speed Racer: Go, Mac Racer, Go!
In a sequence where they are playing make-believe, Mac is seen in a spoof of the end of the opening sequence of the 1960's Japanese anime Speed Racer. Not only that, the look parodied the Dexter's Laboratory episode "Rock 5".

The plot to this episode is eerily similar to the movie Jumanji in which animals come out of the game and the boy and the girl need to finish the game to remove the monsters.