In Twilight Imperium 4th Edition, the Sardakk N'orr have a special version of the Dreadnaught called the Exotrireme. The upgraded version of this, the Exotrireme II has the ability:
After a round of space combat, you may destroy this unit to destroy up to 2 ships in this system.
Who chooses the targets of this ability? The Sardakk N'orr, or the player they are fighting in combat?
Note that if the Sardakk N'orr can chose the targets, this means they can sacrifice a Dreadnought (4 cost) to kill an enemy War Sun and a Flagship (12 and 8 cost respectively).