The kids visit the Big Pond to attend the Biome Block Party. While attempting to win the leaf-necklace contest, Keenan Chirostemotes claims the Pteranodon sibs can't compete for the prize for "dinosaur" with the most leaves because they are not dinosaurs. This launches the kids into a song called "That's Not a Dinosaur", as all the non-dinosaurs sing their piece. In the end, the game rules are changed to include all creatures, even non-dinosaurs, in all the contests.
—Anonymous