Dream Cynthia used her Rayquaza to battle Dream Groudon and Rayquaza used Ice Beam, freezing Groudon. Groudon was able to free itself but Rayquaza knocked Groudon out with a Hyper Beam. Cynthia and Rayquaza later battled against Ash and his Pikachu. Pikachu was able to defeat Rayquaza with a Thunderbolt. The heroes wanted to escape and Rayquaza fused with Mismagius, attacking the heroes and preventing them from escaping. The heroes tried to defeat Rayquaza with their Pokémon which eventually succeeded.