Tap one of your Mandalorians If the unit you tapped to pay the cost is still in its arena at the end of the battle step in that arena, it gets +1 power, +1 health and Stun 1 until end of game.
Keywords
Stun
Stun X: A cumulative ability triggered during the damage placement POP that means, "When this unit damages another unit, that unit gets –X power until end of battle." If no damage counters are placed as a result of damage, Stun doesn't occur. Stun works anytime the unit damages another unit, not just when it attacks. Only the unit with both Deflect and Stun abilities can stun when it activates its Deflect.