Play a Complication
You may pay power to take any card from your hand (hero or villain) and place it at the current mission. The card becomes a complication, and adds 1 to the difficulty of the mission.
The cost to play a complication is 1 power, plus 1 power for each other complication already at the current mission. If you don't have enough power to pay this cost, you can't play the complication.
The first complication you play at a mission costs 1 power. A second would cost 2 power, a third 3 power, and so forth.
If a complication is somehow destroyed after it is played, it no longer affects the cost of subsequent complications.