Batman and Robin in "The Dynamic Trio"

When wanted American criminals begin showing up abroad, Gotham's mayor lays into Commissioner Gordon about the GCPD's inability to apprehend fugitives. The mayor demands that Batman and Robin take on the case. When Vicki Vale interviews Batman about the opportunity, the caped crusader reveals that he's bringing in a third person to help take down the ring of crook-smugglers, a new costumed crime fighter known as the Mysteryman. Shocked by the announcement, Vicki Vale vows to discover their new partner’s identity.

Roy Raymond in "The X-Y-Z Ray"

Martian Manhunter in "The Phantom Fire Alarms"