A mode where I could pick 5 characters from the inventory of a member in my guild and 5 characters from my inventory and have a battle. No rewards. No cost per battle. Unlimited battles. A place to easily experiment with my characters without having to use energy, crystals, or money. Would increase screen time on the game and still keep the incentive to spend money on the game for people who want to. Just a mode for experimentation for all and to help new players understand which characters work well together and how different squads work together.