The bacterium Proteus mirabilis is a cause of urinary tract infections and has a particular predilection for the kidneys. It is named after Proteus , the character in Homer’s Odyssey who “has the power of assuming different shapes to escape being questioned” This is an apt name, because this organism displays a striking morphogenesis which involves periodic oscillation between a specialised and hypermotile swarmer cell type and a form which remains stationary and grows. The cumulative effects of movement and differentiation results in colonies that have a unique structure that appears like concentric circles. It’s easy to imagine this bacterium growing like the expanding ripples on the surface of a pond that emerge after a stone is thrown into it. With this in mind, I decided to subject this bacterium to Young’s Double-Split experiment using blue water colour to define the slits. This is a seminal and unsettling physics’ experiment that demonstrates that matter and energy can display the characteristics of both waves and particles, and which also reveals the fundamentally probabilistic nature of quantum the world. Here’s what happened.