In this activity, students learn about the important topic of invasive species, specifically Zebra Mussels. Students role-play different characters in a real-life situation: the trial of the Zebra Mussel for unlawful disruption of the Great Lakes ecosystem. Students will also learn about jurisprudential inquiry by examining the trial process. This activity will reinforce important knowledge and skills underscored in the Life Science and Science in Personal and Social Perspectives Standards in the National Science Education Standards (National Research Council 1996). (Contains 2 figures, 1 note and 11 resources.)