S1·E33 You’re Going Down Clown

Dan must battle the Pyrus Lord, Apollonier, in order for him and his friends to return to their world. He and Drago soon find out that they're battling a clown. Dan manages to win the battle, but Drago doesn't evolve. When Dan rips off the clown's mask, it turns out to be Runo. In order for Drago to evolve and Dan to past his test, he must battle, and win, against each of the Brawlers.