This is a Random Event. Occurs in:
The intro text for this event varies, and could be any of the following:
- A derelict and still smoking Mantis vessel floats by. The battle must have been recent; its surviving crew beam aboard. Prepare for a fight!
- Your world, all of a sudden, changes. The Mantis are on board your ship.
- You hear a grating rattle and a soft clicking. You reach for your pistol.
This event is called "MANTIS_BOARDERS" in the datafiles.