Hanenbow is the name of a type of Electroplankton in the video game of the same name. In the video game they produce sounds by hitting and retracting off of leaves. A stage based on the Hanenbow was present in Super Smash Bros. Brawl for the Wii.
Hanenbow look almost like tadpoles. Despite this, they're pink and have yellow tails. Their face almost resembles a pink Pac-Man, though it has and odd, "0" shaped eyeball. Like all species of Electroplankton, Hanenbow's design is very simple.
To play the Hanenbow based stage in Electroplankton, the player must drag the various leaves using the stylus, changing their position. One a Hanenbow hits the leaf, it will retract and produce noises. The leaves will also start to change colors, gradually turning red. When all the leaves turn red, a flower will sprout at the top. In the Super Smash Bros. Brawl stage, this would also occur if the players changed the colors of all the leaves by hitting them.