Captain Marvel Adventures #140 (1953)

A barge is out on the unexplored waters of the Swamp Sinister, which is believed to be taboo. Aboard is Betty, a brave young woman working with a crew of archaeologists and also Billy Batson, Boy Broadcaster of Station WHIZ. They are here to find evidence of some kind of “ancient monster” there and the barge is suddenly rocked violently by alligators ramming into them, sending Betty overboard! Billy calls SHAZAM, summoning Captain Marvel who shoves the alligators aside with a log and drags Betty to safety. He decides to dive into the muck himself and drags out what looks like a dead giant found preserved in the swamp, which they decide to research more tomorrow. That night, Billy recalls something was clearly pulling them into the swamp and hears a weird sloppy noise and screams from a nearby tent. Calling SHAZAM, Captain Marvel soon finds what he believes in the dark to be some form of python coiled around Betty and wrenches her away from it. It escapes into the night, but in the morning, they find it's seemingly more like a giant hand, since it leaves very in-depth fingerprints in “walking” around. They clean off the giant and find it's indeed missing a hand just before the animated hand lunges at them from the brush and begins attacking the scientists again. Billy calls SHAZAM a third time and summons Captain Marvel, who is distracted when it punches him into a tree and throws a whole constructed tent into him, then leaps into the swamp. He reasons that this is a good reason that this swamp might be considered “taboo” and decides to send Billy in as bait to lure this creature out again. That night, Billy heads out to look for the Hand, only to be hit in the head by a rock and thrown into the swamp, where he wakes up. The Hand returns to the Swamp Giant, which revives its whole body. Billy manages to strip his clothes off to get to the surface of the water without drowning and call SHAZAM, summoning Captain Marvel, who punches the Swamp Giant back into the swamp to return to sleep, defeated. Later, Billy signs off with Betty saying that they got plenty of pictures of the giant beforehand and that it's probably some kind of strange unexplained magic.