The Japanese multimedia and installation artist Toshio Iwai has directed his interest towards the development of interactive audiovisual installations and software since the mid-1980s. After a first music video game, Otocky (ASCII 1987), he developed the installations Well of Lights and Music Insects during a residency at the Exploratorium in San Francisco in 1992. Music Insects, which works with a computer simulation of sound-generating creatures, can be seen as the prototype for the development of the game Sound Fantasy, which Iwai created for Nintendo in the early 1990s, but which was unfortunately never published. With the game Sim Tunes (Maxis 1996), Iwai was able to realize his vision of autonomous sound-generating insects whose behavior is influenced by the players. The starting position, direction of movement, and speed of simulated bugs in different colors, in interaction with other parameters, affect the melody, key, and tone duration of the music generated by the players and the system. This is why Sim Tunes can be regarded as the direct predecessor of the game Electroplankton (2005) Iwai developed for the Nintendo DS console. It differs from classic computer games in that there is neither a winner nor a rating system. It is composed of ten different types of music games, which are named after different types of plankton. Biological phenomena are used as visual and functional metaphors that are employed to generate images and music. A game like Electroplankton is a very good example of the fusion of conventionally different functions like composing, performing, and perceiving in the field of the audiovisual. The game clearly aims for a personalized and interactive audiovisual-aesthetic experience, where the roles of composer, performer, and audience converge in the individual player. This is significant to the extent that here a new and special dimension can be recognized within the broad field covered by the term visual music. Perhaps it seems a bit far-fetched to call an audiovisual simulation system like Electroplankton a musical instrument, but there are several indications in this direction, especially because the game offers numerous innovative interaction possibilities for manipulating and influencing sounds using biophysical metaphors.