Brawl Stars and Duolingo have launched a global in-app crossover to bring their green mascots Spike and Duo into each other’s worlds. Taking place from September 19th through September 30th, the collaboration follows weeks of the two mascots trading jabs in comments before their rivalry moves into the games. Both apps also introduce new events and exclusive rewards. In Brawl Stars, Duo takes over Starr Park as the game’s latest boss, bringing players into his classroom for a series of challenges.