Luminarrow plankton are famous for their habit of perfectly following arrow-shaped formations. The plankton spin as they move, changing directions as soon as they come in contact with an arrow that's pointing in another direction. The pitch of the sound they make will change depending on where the arrows are positioned. There are four types of Luminarrow: red, yellow, green and blue. Each type floats at a different speed and makes a distinctive musical tone. The four types of Luminarrow drift together to create beautiful melodies. Completely alter the direction of the arrows to change their sound dramatically.