User blog comment:Blinkn/How does Flash fight?/@comment-1031179-20131203011012

He can vibrate his particles enough to pass through solid objects, can rapidly disarm hordes of alien invaders, and can move fast enough to pick up wounded heroes and move them to safety. He can run really fast around a powerful enemy, and wrap them up with a cable to slow them down, or make a tornado to hurl them away someplace perhaps.

If he vibrated a stick he was holding, enough to pass into a solid object, such as an enemy, he could then kill them with that. Or move fast to his enemy, grab them and shake the daylights out of them, vibrating them so they were able to pass through the ground, and then release them, and they'd die. Or pull all the air out of the lungs of someone. But that'd be too easy, and they don't like to kill.