Developmentally, middle school students progress from being concrete thinkers and learners to abstract thinkers. Traditional middle school mathematics instruction introduces a curriculum that is intuitive and taught within a natural trajectory of the content. However, with this traditional approach, students may miss out on being exposed to challenging and complex topics from advanced mathematics that can greatly expand the way that students think mathematically. Concepts such as infinite sets can be counterintuitive, but they can hold the interest of most students. Perhaps this is because of their inherent eccentricity, which is counter to students' natural ability to easily adapt to finite objects and events. Although there are various avenues to introduce these complex mathematical topics, the authors propose an activity about the concept of infinity that highlights the importance of proof and reasoning and expands the learner's abstract thinking. (Contains 1 figure.)