In a battle you usually attack first, but sometimes your enemy takes the first turn, and sometimes it changes back to you being the first.
What's the logic behind it?
31 Answer
There's is indeed a speed stat, and the Morty on the field with the higher speed would move first. This can be permanently raised by levelling up, or by using the "Speed Mega Seed" item. If a speed-affecting move like Gross Out or Pout gets used, it will also change the turn order during that battle. The Paralysis ailment probably has an inherent speed debuff, too.
If you chose to swap your Morty out when two Mortys are already in battle, it will happen before they hit you for that turn--even if they're faster than you--but they'll get an extra hit on the Morty you send in.
