It started with a potato gun, some spare time and a group of Canmore, Alta., teenagers looking for something to do on Halloween night. Nearly a year later, the result is a seven-foot-tall homemade tank weighing close to a tonne—an unusual sight that drew honks from passing motorists, attention from trick-or-treaters and more than one encounter with the Canmore RCMP. For 16-year-old Tatum Hilhorst and his friends Finn Cohen, Cedar Paterson and Caden Wallis, what began as a small Halloween project grew into an ambitious engineering experiment that took hundreds of hours to complete. The idea came about during Alberta’s 2025 teachers’ strike, when the teenagers had extra time on their hands. “We built a potato gun, and then we needed something to put it on,” Hilhorst said. “So we thought, what better way to spend our time than by building this giant tank?” The group had already built a small cardboard tank to carry it, taking their first version out for Halloween that year. After dismantling it, they decided to try something bigger and began working on the new project in November 2025. They called the new creation Potanzer II, combining the word “potato” with “Panzer,” the German word for tank. This time, the teenagers wanted to build something more ambitious, spending the next year developing designs, working out the mechanics and sourcing materials. “We have a whole spreadsheet. We have budgeting, weight approximations and everything,” Hilhorst said. The plans changed as construction progressed, with the group adjusting their designs and learning from mistakes along the way. Built a tank from the ground up The finished vehicle has a wooden frame covered in cardboard and painted grey with an estimated cost of $5,000, which was funded by several people working on the project. Tracks along the bottom sides of the tank are decorative, with rubber wheels underneath allowing it to move, but it has plenty of extra bells and whistles. An electric motor powers the tank, which also features headlights, brake lights, turn signals, a rotating turret, fans, a backup camera and even a mini fridge. The original potato-gun concept also made its way into the new build with 3D-printed shells that can be loaded into the gun and fired from the tank. The electrical systems are split between two power sources. A 12-volt system runs the lights, fans and cameras, while a separate 48-volt battery bank powers the 1,800-watt motor. Cohen took on much of the electrical work, drawing on experience with projects at home. He also calculated what kind of motor the tank would need and how fast it could travel. “I did a whole page of math. I learned all of it myself to calculate what type of motor we might need and what kind of speeds we could get,” Cohen said. “After I crunched the numbers, it was pretty darn close to my prediction, and we were so happy to see the tank moving.” On flat ground, the tank can reach a top speed of about 15 kilometres an hour. The teenagers worked on Potanzer II after school, during the summer and on weekends, often putting in full days at a time. “There were many weekends where we just were there for both days of the weekend, like maybe eight hours at a time,” Cohen said. For Hilhorst, the time spent working on the tank was just as valuable as the finished product. “I got the chance to spend so much time with my friends,” Hilhorst said. “Like, way more than I would have if we were doing anything else.” Getting the tank out for Halloween With construction complete, the group turned its attention to getting the tank out for Halloween. The teenagers approached the Town of Canmore to ask about obtaining a permit and whether there was a way to make operating the vehicle as legal as possible. “That was a challenge because there’s not really any permits for tanks,” Hilhorst said with a laugh. “We did have a couple encounters too with police, but it was mostly positive.” The group had made contact with RCMP after an earlier test run took them farther into town than they should have gone. On Halloween night, the teenagers kept to residential neighbourhoods, avoiding main roads and travelling long distances across town. The tank quickly became a spectacle, and a highlight of the night for trick-or-treaters and community members who took photos and videos with the vehicle up close. “Seeing our project come to life for the first time was such an awesome experience,” Cohen said. “It was really quite fulfilling to see everyone come together for this project.” What’s next for the tank? The teenagers are already considering what they could build next. Hilhorst said they have talked about making another version, potentially learning skills such as welding and using metal. The project has also given the group a chance to explore their interests in engineering and hands-on work. Cohen said he is interested in pursuing a career involving building, math and physics. The teenagers encouraged other young people to try their own projects, even if they start with something much smaller. “It doesn’t have to be as big and crazy as this thing right here. Just do something small and build your way up,” Cohen said. “It doesn’t have to be the most amazing thing the first time you try, but it’ll get better the next time.” Hilhorst also said projects of this scale require space, money and a significant time commitment, but believes the experience is worth it. His advice to other aspiring builders: “Try to do it the best you can without getting in trouble!”
