Haney, Trapani and Paris have Metamorpho fight, essentially, the Metal Men in issue 12 (May/June 1967).
The story begins as Simon Stagg hosts a million dollar competition to find a cure for Metamorpho. We see that Stagg still has no real intention of healing Rex Mason, and is looking for a crackpot with a convincing plan, just to mollify Metamorpho, and keep him under his thumb. Sapphire Stagg and Java are in the issue, but neither does anything other than play their usual roles.
We also briefly get to see Element Girl, still lying dead-ish in the lab. The man who Stagg allows to work on a "cure," Zorb, has no real intention of doing so. Instead, his goal is to use Stagg's lab and resources to build a set of element based robots, the Chemo-Robots, who function much like the Metal Men do.
Once the robots are working, Zorb uses them to destroy the Stagg mansion. Metamorpho has to go into action to rescue Stagg, Sapphire and Java. The action then shifts to a university, where Zorb plans to use the robots to steal a "nucleonic moleculizer projector" being developed there.
The climax of the story has the robots dressed up as football players, with Metamorpho battling them on the field. The projector is hidden inside the football. It's all fairly silly. As the issue ends, Simon Stagg kicks the football away from Zorb, which causes the projector to be activated.
The story continues in the next issue.