This may be an issue more than an idea but I wasnt sure where to post it. I ran into the issue where an AI was using an obliterator behemoth and was running it past my system blockades. Then it would fire a shot and move on before i could get it. Because the AI would wait to move its fleets till after my turn was over, it could take all its actions without me ever being able to target it, hitting my systems with the obliterator shot while i was helpless to destroy the ship. Ive only ever seen behemoth ships do this. Its really messed up.