Wouldn't he zzzzzzt himself the first time he did something foolish?

Also this issue: Man-Thing gives a shack the what-for. From 1974, Man-Thing #3, "Day of the Killer, Night of the Fool!" Written by Steve Gerber, pencils by Val Mayerik, inks by Jack Abel.

We start with the shack, which wasn't a harmless construction shack, but was in actuality a trap set for Man-Thing by his foes, contractor F.A. Schist and Professor Wilbur Wickham. They want to kill Manny real bad, although this issue doesn't get into why. Man-Thing was usually placid and somewhat lethargic, but today he seems to remember that trap, and smashes the crap out of it, scaring of Schist and company for now.

Nearby, Richard Rory (...ugh) says goodbye to some new friends; namely some bikers that were going to kill him but now like him. Unfortunately, Richard forgot to ask them, or the cops that were also there earlier, to borrow some gas, so he and his girl Ruth are still stuck there! His biker friends are even less fortunate: they ride smack dab into the Foolkiller, who stops them with his "purification" laser pistol. FK is searching for Rory; to their credit the bikers don't give him up, and are both killed. (The fate of their girls is unclear, if they survived the bikes exploding, but Foolkiller doesn't question them or check.) Foolkiller then heads to the F.A. Schist construction camp, to give Schist his card:

Later, a familiar seeming sports car stops to help Rory and Ruth, before heading up the road: while grateful, Rory has a feeling "as though he's had a meeting with destiny--and slept through it!" Even though he's in costume again the next page, that was pretty obviously Foolkiller helping Rory out, but he misses his first target en route to his third: Dr. Theodore Sallis--the Man-Thing! Somehow, FK had accessed the secret "Serum SO-2" information, and put together what had happened to Sallis. (Which would seem obvious if you read comics, but a bit of a jump in-story!) He is distracted by a helicopter, which in another logical leap he assumes is Schist trying to escape, and shoots it down. Instead, it was innocent bystanders escaping a flood, now crashed into a swamp and surrounded by gators. This unforced error seems to jar Foolkiller, so he's slow to respond, but the Man-Thing lurches into action, throwing the gators around and saving the people.

Foolkiller says he will reconsider Manny's death, but in doing so calls him Sallis, which seems to trigger the same response that saying "Banner" to the Hulk did. Feeling the hate in FK, the Man-Thing advances on him, and is gunned down by repeated laser blasts. The second-to-last panel has a Marvel Value Stamp cut out of it, but still a good line: "And finally...when his insides are dry as chalk" the Man-Thing falls, dead. Well, 'dead,' I'm pretty sure like a large Gatorade would reconstitute him. I also know the Foolkiller gun and costume have been passed around a bit, but I had forgotten the religious crusade aspect of this one. Although he seems less 'avenging angel' than 'dangerous lunatic,' Gerber probably won't make a paladin of him.