Hanenbow, known as Electroplankton (エレクトロプランクトン Erekutoropurankuton?) in Japan, is an unlockable stage in Super Smash Bros. Brawl. It comes from the music-themed Nintendo DS game Electroplankton, which features extensive interactivity with the microphone.
The stage consists of multiple stems with leaves branching out on each stem. It also features the Hanenbows being fired at the stage's platforms, which make a musical note on contact depending on the angle of the platform. The platform's angle, position, and color can be changed by attacking them. Note that the branch on the left can't be stood on (although it serves as Pokémon Trainer's platform). When all the leaves on the right-most tree are a dark red, a flower sprouts on top of the tree, making another sound effect. This is a key aspect in an event match on the stage, as the flower must be sprouted while avoiding Olimar's attacks while playing as Peach to clear the event and unlock Hanenbow.
This stage is the one of the only two where a character can't swim in its water, the other being Corneria. It is also the only one to have completely interactive music.
Interestingly, all characters in this stage and the stage itself are in 2-D, much like Flat Zone 2.
This stage is banned in tournaments due to irregular stage design that makes it difficult to traverse, ungrabbable ledges, being overly large, and powerful camping spots, particularly on the bottom left leaf. The sloped leaves can also negatively affect gameplay.
Electroplankton is an interactive music video game developed by the Japanese interactive media artist Toshio Iwai and published by Nintendo for the Nintendo DS. This game allows the player to interact with animated plankton and create music through one of ten different plankton themed interfaces. One of these was called 'Hanenbow'. The Hanenbow interface looked exactly like this stage does. In it, one would move the leaf on the bottom around the screen, both rotating it. Small fish called Hanenbow would use the leaf like a ramp, and would make a sound as they hit the other leaves. The sound would change depending on the speed of the hanenbow and the angle of the leaf. The leaf would also change colours as it was hit, going from green, to yellow, to red. If all leaves on the tree on the right were red, a flower would sprout, and a sound would be made. When the Hanenbow hit the water, they sink.
In Brawl, the bottom leaf can be rotated. When a Hanenbow hits a leaf, it makes a sound just like they do in Electroplankton - the sound is based on the speed of the Hanenbow and the angle of the leaf. The leaves change colours when they are hit either by an attack or by a Hanenbow. If all leaves on the right tree are red (the tree on the left is not present in the original version of this Hanenbow level), a flower will sprout, but this doesn't effect the battle in any way, other than the screen zooming out so that the flower is visible. The stage's 2D nature is representative of the 2D, almost paper-like, art style of Electroplankton. The reason for characters not being able to swim in this stage is probably a reference to how the Hanenbow would sink when they landed in the water.
- An assembled Dragoon, Snake's taunt and Final Smash, and the Ice Climbers' Final Smash (along with "sparks" that appear when a character is hit) are the only things in 3D, but effects such as the reflections on the Landmaster and Samus's armor still look as though they are 3D.
- Whenever a character gets Star KO'd or Screen KO'd, both the character and the effects fly off separately. This can be best seen from Olimar's beacon on his antenna, the flame on Charizard's tail, and whenever a character is frozen. This also happens in Flat Zone 2.
- This stage has no My Music, even though an ambience track can be found in the game's data.
- If Sonic stands on either of the two leftmost platforms on the top or the leftmost platform on the bottom and uses Spin Dash, he will go flying directly to the right and off the stage. This is known as the Spin Glitch.
- All leaves can turn red, except the one in the bottom left corner, because it is the only one in the original Electroplankton level that cannot be hit by the Hanenbow.
- When a fight begins, the sound of a full orchestra tuning (as in the opening of Electroplankton) can be heard. However, the only sound made by the Hanenbow striking the leaves is that of a xylophone.
- Hanenbow and Flat Zone 2 are the only stages in Brawl in 2-D.
- Overall, this is the third stage that is flat, the first being Flat Zone and the second being Flat Zone 2.