Hanenbow is an unlockable stage in Super Smash Bros. Brawl. It can be unlocked by clearing Event 28, Flower Blooms in the Echoes. It is an odd-looking stage from an obscure series, Electroplankton. No music plays on this stage. Instead, hitting the leaves produces sound.
The main platforms of the stage are the leaves from the plants. The leaves change their angle upon getting hit as well as getting closer to a deep shade of red. Tadpoles periodically appear hitting the leaves and increase the shade. Once all the leaves are red, a flower appears at the tip of the plant, with each plant activating separately. The leaves slowly regress to their initial shade of green when they aren't being hit. Despite their frail look, the edges of the leaves can in fact be grabbed.
The water below the stage doesn't act like water. Instead, players who fall will disrupt the water creating wave patterns. Characters fall at the same speed as through air. However, there is little chance of recovery due to the stage's size and the distance from the wster to the plants.
This is one of the only 3 stages in that the entire stage is rendered in 2D in the series, with the other two being Flat Zone and Flat Zone 2.
This is the only stage without premade music. The reasoning is likely because the series it's based on is a music creating game by interacting with the level's features so, the fighting creates the music.