In Daredevil #30-32 (July-August, 1967), Stan went a little too far on both counts. The series features Daredevil against the old Thor villains, Mr Hyde and the Cobra. Matt figures out that they must be behind the series of robberies in the city. And since he reasons that he can't just patrol the city to find them, he decides to dress up like Thor to draw them out.
Well, you can probably see the fly heading rapidly towards that ointment. Sure enough, Don Blake hears that Thor is plying his trade in midtown and pounds his cane. Before you can say Ragnarok, Thor and DD are doing the classic Marvel, "I'm a hero and I know you are too, but let's fight for a couple pages so they can put it on the cover!" routine.
But eventually they stop clobbering each other and Thor flies off. And the villains DD had been hoping to attract show up. At first they attack him, but Mr Hyde has a better plan--let him follow them back to their nearby lab, where:
Well, the stuff in the test tube is supposed to make one blind. But since Daredevil is already blind, it has no effect, right? Heheh. Sorry, Marvel science doesn't work that way. Since he's already blind it takes away DD's special powers of hearing and the other senses he uses to compensate for his blindness.
Okay, so the hero's up in the branches and leafs and the stones are being hurled at him. But the story takes a twist. Mr Hyde and the Cobra, sensing that DD is no longer a threat, abandon him. DD somehow manages to find his way back to his apartment (apparently not thinking of changing his clothes). Matt does some heavy thinking. Since Foggy and Karen know DD is actually Matt's supposed twin brother Mike, if Daredevil is suddenly blind he'd better make sure that Mike appears to have been blinded as well.
And if the logic of that is as impenetrable to you as it is to me, congratulations, you've been paying attention, because none of this makes a whole lot of sense. So Mike shows up at the office, displaying signs of having lost his eyesight. Karen of course reacts selflessly:
Fortunately the tender scene is broken by the Cobra and Mr Hyde, who have taken up occupation of a nearby rooftop and are threatening havoc. So Mike gets into his DD duds, gets Foggy to help him up to the top of their building, so he can throw his billy-club line across to the villains. And DD tight-ropes his way across the wire, blind and unaided by his other senses, which freaks the crooks out so much they take off.
But they come back and realize that DD is indeed still blind. So they decide to take him back to their lab. Their other lab, not the barn they were in during the battle two issues ago. This one is in a lighthouse. DD goes along with them because he knows he needs the antidote, which Hyde has surely prepared for his blindness potion. And of course once they get to the lighthouse there is a battle, DD eventually gets the antidote, and fortunately guesses right that it has to be swallowed, not splashed on the side of his head like the original potion:
From there, DD makes short work of the Cobra, although Mr Hyde is able to escape. It's an entertaining storyline overall, but it strains credulity to the snapping point. The stones are too rough, and the way that the hero gets down from the tree is not believable.
