Justice League of America, Vol. 1

Answering a distress call from Batman and hawkman, the Leaguers - along with Zatanna - are surprised to find the pair of heroes acting as if nothing is wrong while a giant robot excavates an archaeological dig behind them. When pressed, Batman becomes enraged and commands the robot to destroy the League which it does so.The League, though, planned ahead and used duplicates created by Green Lantern's power ring to fight the robot. They track the signal it sends back to its home planet which lay in ruins. Here they find the Assemblers of Angor whose own home planet had been ravaged by another of the robots. The Assemblers mistake the League for the creators of the robot and attack them before Zatanna heals one of them, proving them to be peaceful.