Sea spiders. Yes, they look like green crabs, and the idea of spinning webs underwater seems farcical, but there is a real world analog here, the diving bell spider.
Perhaps more important is the question, is this really an underwater adventure? It's very hard to tell from the art if Buzz Crandall's adventure is meant to be underwater or not.
It's an odd bit of hideout design that the control room for the torture chamber are on top of a high wall overlooking the chamber. More interesting is that the "shark-men" are not interested in medieval torture, but use hi-tech methods like freezing gas.
Okay, there's some science-y nonsense about "lodium" being a naturally magnetic element that powers a raygun able to cross the entire universe, but what interests me here is that the most important planet in the universe isn't Earth, but Pluto!
So what's so special about Pluto in the year 2000? The colonists on Pluto have clearly mastered climate control, because they've changed the planetoid from 387 degrees F to temperate enough that all the men go shirtless there.
This starts out as another unexpectedly nice touch, having the action on Earth start in India, rather than the U.S. Then it takes a peculiar turn by having the men in the Indian observatory be white. Is this a nod to globalism, or just a racist thing? You decide!
Also, look at that magnification! That is also a more powerful telescope than any we had in the real 2000.
Ooo, more future predictions that nationalists would not like. This 2000 has one world government already! Also interesting is how it is based in Switzerland, giving this future still more Euro-centrism.
These were called "sky dreadnaughts" on the previous page, which is a cool name for a fighting transport ship, so it's a shame that these wound up looking like such "traditional" rocket ships.
Lt. Blake is either delusional, tripping on acid, or these sky dreadnaughts can go Warp 60. It takes light about an hour to travel from Mars to Saturn.
Also bear in mind that it's been minutes, maybe even an hour, since Pluto was attacked -- not one of the inhabitants has bothered to put on a sweater or even a shirt in all that time. Maybe, despite how important this planet is, they don't own any.
I'm beginning to doubt that Quorak is really on the other side of the universe.
One bit of real science here -- a magnetic ray would likely disrupt electrical equipment on a space ship, like an EMP.
(Scans courtesy of Digital Comic Museum.)