"Unusual Tales", a series presenting Steve Ditko's comics from 1957 to 1959 that are in the public domain.
"The Thing From Below" is a 5-page story first published in Charlton's OUT OF THIS WORLD #5 [1957]. An excellent monster story about a professor who goes around the oceans using an ancient formula that he believes is bait for a sea monster. Apparently he didn't think too far ahead, as the emergence of an actual sea monster scares him spitless, leading to a very 1950s ending. Some great work by Ditko, especially on that first page.
Though there's probably no way to verify it one way or another at this date, I wonder if the gorgeous cover to UNUSUAL TALES #6 [1957], a few months prior to this issue, goes with this story. It certainly does fit, though the monster design is different, and there are more men on the boat, and they look more like recreational fishermen than researchers.
But before the story, some links:
Classic MR. A comic reprint available now
Chock full of fan art, article and Ditko rarities
1980s Deluxe THUNDER AGENTS reprint coming soon
Scans in this series generally adapted to my personal tastes from those copies
As this story appears in the Snyder/Ditko KONGA #25 [2018], I'm only including the first page below.