"Thunderbeam" is an episode of Special Agent Oso.
Professor Buffo makes Oso test the Hydro Bubble to walk on water. Oso's mission is to cross the lake and get onto Wolfie's boat. But as he nears the boat, he gets tired from walking on the water and then gets swept away by a waterfall. That's when a special alert comes in. A girl, Leah, wants to join the Green Group Gymnastics after watching her older sister Kyra walk across a low-level balance beam. But Leah is prohibited for taking part because she can not do it. So it's up to Oso to teach Leah how to cross the balance beam to join the gymnastics before the class starts.