Unless we can find out who or what he is and where we can comer our invisible assailant, we can't do anything more than shoot down the robot ships sent to attack us.

Then he attempted to go through life with skips and swaggers, only to reel from the punches of invisible assailants.

His hair blew one way, his night-gown another, his legs threatened to float from under him, and his head to grow dizzy with the swiftness of the invisible assailant.

One was struck by an invisible assailant, who then grabbed his weapon and cracked him across the face with it.

It seemed to be engaged in a struggle with an invisible assailant.

They continued to wrestle with invisible assailants as Laintal Ay drew the cover across the grille.

An unidentified young woman, alone in a room, is attacked by an invisible assailant, who hangs her in the stairway of her house.

This too thudded home into her invisible assailant.

His men were fighting wildly against the invisible assailants; Damon, clutching the matrix, wheeled his mount and swerved, dashing away from the attackers at a hard gallop, and down the path.

Denis seemed to be struggling against some invisible assailant He staggered, then his body convulsed as though shocked by a bolt of electricity.