What could be more Halloween than a costume? Two costumes?

So I picked up today's issue in a pile of old Superman's, including anniversary issue #400 and nuclear-war cautionary tale #408; and it's closer to Silver Age-silliness than either of those. From 1985, Superman #405, "The Mystery of the Super-Batman!" Written by Craig Boldman, pencils by Alex Saviuk, inks by Karl Kesel.

Lead story on Metropolis GBS News tonight: Superman, stopping a museum heist...while wearing a Batman cowl? No explanation why, at least, not that he gives to anyone; except later Clark Kent makes a quick call to Bruce Wayne. With Bruce out, Clark leaves a message with Alfred, that he would explain later. As much as anyone could explain suddenly growing satyr horns.

While Lana Lang's archaeologist dad showed them some new museum acquisitions, Lana blew on "the Syrinx of Arcadia, golden pipes of Pan; which magically caused Clark to grow horns. Because of course: I have to wonder, if Supes hadn't been there, would Lana's dad have grown horns, or was Supes just susceptible to this kind of thing? As Superman, he then tries to get the Syrinx to figure out how to cure himself, and of course it's being stolen. Grabbing a cowl from a Batman display in his Fortress of Solitude--back then he had displays of all his friends, nothing weird about that--the Super-Batman would stop the robbery, but the pipes recovered were a fake. Clark then has to track the pipes down, while making excuses and covering his horns with a hat or helmet at work. (Shades of Bongo's Radioactive Man there!)

It's total fluff, and Supes treats it that way too: by mid-story, he's less concerned with curing himself, then with scaring a criminal type with his masquerade. Which he doesn't, until he takes off the cowl, because the criminals were just confused before...