Petri Dish is a dice-driven contest between pyramidal micro-organisms. This Looney Pyramids game had a long pre-history as an unpublished prototype before its first publication as part of Pyramid Arcade. Each of 2 to 10 (!) players has nine pieces, of which four start in play. The goal is to eliminate all of the other players' pieces, or to get all of yours onto the board. Each turn, a player takes three actions, constrained by the throw of a set of three custom dice.