Opto-Phono-Kinesia (OPK) is a body-based audio-visual performance piece. The title is a play on the possible synaesthetic state involving connections between vision, sound and body motion. Theoretically, for a person who experiences this state, a specific colour could trigger both a sound (i.e. a particular note) and a body action (i.e. a flick of the hand). This synaesthetic intersection is simulated in OPK by simultaneity of body movement, and audio-visual result. Using the Gesture and Media System 3.0 (GAMS) motion tracking system, the performer can dynamically manipulate a complex audio-visual environment using two small infrared trackers. Conceptually OPK makes a case for physically-engaged interaction in response to much of present-day ‘lazy media,’ while at the same time the piece subtly references possible damaging uses of those technologies.