Guests, Parasites and Symbionts, is an interactive art and biology installation in which visitors will engage with live organisms derived from their own bodies and from those of other participants. Using the techniques of biology and medicine, the installation proposes to make visible these organisms and to create an engaging and provocative media environment for the interaction. It is based on what I already did in Protozoa Games. In this new version visitors will make physical contact with some device that will acquire their organisms. It then will provide for immersive sound, video, and animation events in which the flow of events are controlled by the interactions of the visitor's movements and gestures in the space (read by motion tracking technology) and the movements of the single cell organisms that are part of their body as made visible by a digital microscope. A projection screen will project their microorganisms situated as part of interactive digital animations and video created in Director. Another version of the installation will allow multiple visitors to engage with each other and each other's organisms and another version will let web visitors engage the protozoa.