What causes the rocket ship to launch in Pokémon Pokopia’s ending?

In Pokémon Pokopia’s ending, party poppers trigger an emergency evacuation launch.

After Ditto restores habitats and completes the Team Initiation Challenge, Ditto and Professor Tangrowth celebrate with party poppers. The celebration unexpectedly activates an emergency evacuation protocol, revealing that the mysterious structure is actually a rocket ship.

The launch reframes the story’s abandoned-world mystery. Humanity had left for outer space after the environment became inhospitable, while Pokémon were stored in a massive computer system designed to release them when conditions improved. The rocket’s activation connects the restored habitats to that larger history.

The ending is easy to misremember as a deliberate launch sequence or a battle involving Team Rocket. Neither happens: the emergency procedure is activated accidentally by the celebratory party poppers.