The Octopus is an oddity on several levels. One, the title character is that of the bizarre villain featured in its pages. Several times during the pulp years, publishers tried putting out pulps that would contain recurring villains, several of them in the Fu Manchu mold. And, no doubt, the enduring popularity of Manchu as well as characters and books like Fantomas, Frankenstein, and Dracula all suggested that a series based on a recurring villain was feasible.
Two, the first and only issue of the pulp is given as being Vol. 1, #4, suggesting three earlier issues featuring the character is out there. This is not the case. According to Robert Weinberg, it is believed that probably the book is a continuation of Dr. Yen Sin, another failed villain pulp put out by Popular.
Three, the villain's next appearance doesn't happen. Apparently he didn't set the world on fire so the story that was to follow this one, had the name of the villain and pulp changed to The Scorpion. The Scorpion failed to catch on as a villain as well. However, both names would prove popular for villains over the years. There's easily a half dozen Scorpion villains in the comics and movie serials of the time. Fewer Octopi, but his latter day namesake Doctor Octopus is far more popular than all combined.
When I first read the story, I knew it was supposed to be by Norvell Page, the writer behind many of The Spider pulps. Stylistically and thematically it is very similar to the more famous series with much of the same beats and rhythm. The Octopus is wilder though, it's The Spider with the dials cranked up to eleven. There's a rawness to it, that I thought it came first before Page had refined his style and plotting.
However, that's not the case. The Spider was started in 1933 with Page coming on board soon after. The Octopus was published in 1939. Instead of a progression, the Octopus character and story suggests some kind of regression. It's an explosive release of unbridled creativity and writing, piling improbability upon improbability, delivering it to the reader through purple prose and force of will, defying credible disbelief and logical plot progression and extrapolation.
Take the hero, Jeffrey Fairchild. Rich and trained to be a doctor, he runs and operates a clinic under the guise of a kindly old doctor improbably named Dr. Skull. He is also the lethal vigilante known as the Skull Killer due to his marking his victims much like the Spider. He also has secret tunnels between the hospital he helped fund as Fairchild and Skull's clinic. In an unusual twist, he has a pampered crippled brother who is overly critical of Jeffrey but whom Jeffrey bends over backwards to help and is trying to cure as Dr. Skull. Also a bit different from the usual is the would-be love interest Carol Endicott. Instead of coming from the best families, she's from the slums and was persuaded by Jeffrey to trust Dr. Skull who'd give her a job and security. This is a woman who is a bit cynical due to a hard life. When she tries to use her father's gun which blows up in her hands she ruefully thinks, "Poor old Pop! He'd come back from over there with an army gun and a lot of faith in nothing at all. Other men gave their lives, and Pop had given his soul... She might have known he'd never leave her anything useful!" In a roller-coaster story, it's a throwaway bit of deft humanizing characterization.
The villain is one of the most bizarre humanoid villains to grace any pulp. His description is often vague, describing more of the horror than his actual form, leaving it to the imagination. The end result is of some kind of Lovecraftian being in almost human form. What bit of visual description tells us that he has six octopus like limbs instead of a pair of arms. The text implies that the eyes of his mask glow, but the artwork shows it to be lights on part of his bulbous mask. The story at times almost suggests that somehow a Dr. Borden is the Octopus, but it never implicitly states it or how he managed such transformations. However, by the end of the story Borden has disappeared from the pages, no reference of his final fate.
Using ultra-violet light treatments, the Octopus has discovered a way to devolve people but not to bestial, ape-like beings. Instead, their blood is broken down to being like sea-water, their bodies and tissue also breaking down to more gelid matter. Their minds become more primal and violent and coupled with the changes to their blood, they become vampiric. Even though they need and crave the blood, they need regular treatments of the ultra-violet light even more. It is with this that the Octopus begins his reign of terror over the city, all for purposes of blackmail. Though the themes of torture, mutilation and monster-making occurs a couple of times in Page's Spider novels, the resulting creatures and their creator is never as creepily horrific and unearthly as here.
The improbabilities, outlandishness, and sheer audacity of characters and plot would probably deter most readers from this story, though I find it oddly compelling and worthy of re-reading every couple of years to just remind me of the experience. Sadly, while I own two reprints of this novel thanks to a recent reprinting, I've yet to come across a reprinting of the followup, The Scorpion.