Teen Titans / Legion Special #1

The Fatal Five now appear to be the Fatal Five Hundred! A hundred copies of each of five deadly villains face the Legion and their allies, the Teen Titans! Fortunately, Brainiac has a plan. Two speedsters will race on the cosmic treadmill and generate vibrational energy. When this resonates with the Persuaders' atomic axe it will reset the molecular structure of each copy of the Fatal Five, sending it back to its home. But, an unforeseen effect: the axes release energy as they shunt, which disconnects the Legion from its own space time. Superboy manages to hold one axe in a telekinetic field long enough to carry everyone back to the 21st century. But the Legion is swept... somewhere... en route, and the Titans wind up in 2014, ten years after they left!