What I like to call the HP LOVECRAFT cycle on VOYAGE includes the following.
MUTINY (what are the many jellyfish that appear in VOYAGE really working for or scouting for or if not, what are they?). The jelly fish type thing reappears in GRAVEYARD OF FEAR. Another kind, and this time it is linked to eternal youth serum, the serum making a young test subject girl young again. But in what way is it linked? The serum was supposedly created by a team of scientists but was it really? Where did they get the idea and how did they grow the jellyfish or find it? While we are on paranoia here, what really caused the earthquakes in ELEVEN DAYS TO ZERO? And who is behind Dr. Gamma and all the evil agents sent to stop Seaview?
THE INVADERS (this ancient race had many secrets of being on Earth for over 20 million years and were hardly human at all--were they the product of some higher alien life form--an evil one and did they worship any kind of "god"?).
THE INDESTRUCTIBLE MAN (what in space made the robot want to kill? What force was behind this?).
CRADLE OF THE DEEP (while I haven't included any of the scientific findings and experiments such as those from VILLAGE OF THE GUILT, HAIL TO THE CHIEF, THE FEAR MAKERS, THE X FACTOR, etc, there are episodes like those and this one CRADLE OF THE DEEP, that make one suspect human scientists have been given secrets by some higher life form and not for the benefit of human kind).
The monster in THE CONDEMNED and the air mixture invention may have also been something mastered by a master alien race, THE AMPHIBIANS certainly, THE CREATURE I, LEVIATHAN for obvious reasons, THE MONSTER FROM OUTER SPACE, DEADLY CREATURE BELOW (perhaps the monsters like this one were leftover experiments from the early alien to human life original inhabitants of Earth and outer space or other dimensions beyond our vision and such monsters appear in outer space in LOST IN SPACE and this sum up for this monster is not unique--there were other types of creatures seen in space and on Earth under the sea--see THE MONSTER'S WEB, THE MENFISH, THE MERMAID, THE THING FROM INNER SPACE, and others).
THE PHANTOM STRIKES and THE RETURN OF THE PHANTOM (what really brought Kruegar back from the dead? and how did Lonnie fight back--were there two opposing forces of aliens or demons against angels behind this?), ditto demon intelligences or alien or both demonic and alien forces for THE HAUNTED SUBMARINE, CAVE OF THE DEAD, THE TERRIBLE LEPRECHAUN, DAY OF EVIL, THE MUMMY, and THE RETURN OF BLACKBEARD. Ghosts and other supernatural evils were hardly ever fully explained on VOYAGE. Was some devil or evil space alien behind it all or at least some of the time?
To a lesser extent, men turning into monsters can be seen as the experiments or leftover residue from alien interference and VOYAGE has had plenty of those: WEREWOLF, BRAND OF THE BEAST (both werewolf tales laid the foundations of the lycanthropy as a virus disease--but where did it originate from?), and MAN-BEAST. Again, in MAN-BEAST, the result was supposedly from a scientist's experiments but is it really?
THE SKY'S ON FIRE--what really made the Van Allen Belt suddenly lurch towards the Earth--perhaps alien fire beings not unlike THE HEAT MONSTER. As in THE MONSTER FROM OUTER SPACE, we have aliens from space in other episodes. Sometimes these aliens refer to themselves as the Masters of the Galaxy or the Universe. Sometimes they claim to have done this to other planets (and in THE TIME TUNNEL, the aliens in TOWN OF TERROR, RAIDERS FROM OUTER SPACE, THE KIDNAPPERS, VISITORS FROM OUTER SPACE make these claims outwardly). MONSTER FROM THE INFERNO, THE TERRIBLE TOYS, DAY OF EVIL, DEADLY INVASION, SHADOWMAN (which represents the same type of aliens in LOST IN SPACE's WRECK OF THE ROBOT and THE GALAXY GIFT), DOOMSDAY ISLAND (the aliens which resemble the bearded alien in THE TIME MERCHANT as well as the alien scientist Lemnoc in LOST IN SPACE's THE PHANTOM FAMILY), DEADLY CLOUD (the alien which resembles one in LOST IN SPACE that took over John in FOLLOW THE LEADER), THE DEADLY DOLLS, JOURNEY WITH FEAR (most straightforward aliens), TERROR, THE LOBSTER MAN, NIGHTMARE, SAVAGE JUNGLE, FLAMING ICE, and ATTACK! all fall into this aliens are arriving, are already here, or are taking us over realm. The point of masters is driven home most in THE DEADLY DOLLS but "masters" of the ages and the galaxies are mentioned in THE TERRIBLE TOYS and DEADLY CLOUD. Many of these aliens claim to have been watching Earth for a long time. DOOMSDAY ISLAND aliens have been here for centuries.
Another genre falls into the beings from the sea--it is rarely explained if these beings are from Earth originally or if they have come from another planet or were brought here by other beings. Perhaps the sea creatures in these episodes were experiments themselves of some earlier race of monster-intelligences. These include: THE INVADERS, THING FROM INNER SPACE, THE FOSSIL MEN, THE MERMAID, and DEADLY AMPHIBIANS. In addition to this, some of the before mentioned monsters from space had a sea-like feel to them: THE LOBSTER MAN certainly was from a sea planet and the alien's true form in NIGHTMARE resembled DEADLY AMPHIBIANS--was there a link in some way. Again, many of these "races" appear in LOST IN SPACE in deep space--and also look like--sometimes exactly like--the aliens and sea men presented in VOYAGE (the alien in LOST IN SPACE-A CHANGE OF SPACE looks like the merman in THE MERMAID, not to mention the supposedly man created THE MENFISH, an alien woman in LOST's SPACE BEAUTY looks like THE DEADLY AMPHIBIANS). Are they all linked to a small select group of higher life forms---evil ones as well as neutral and good ones? Although I could never imagine Richard Basehart acting against a race of frog aliens, it must be mentioned that these watery type frog aliens appeared several times on LOST IN SPACE (THE GOLDEN MAN, THE GALAXY GIFT). It must be noted that these monsters and "races" are also linked to errant life forms that seem less intelligent at times--the spider in LOST IN SPACE-THE KEEPER PART 2 and THE MONSTER'S WEB as well as other cameos in both SPACE and VOYAGE. This also goes for the white creatures seen in SPACE CIRCUS and REVOLT OF THE ANDROIDS--resembling the mad scientist experiment in THE ABOMINABLE SNOWMAN on VOYAGE. More on mad experiments and well meaning experiments gone awry below.
In addition to all of the above, there are evil scientists, mad experiments gone awry and telepathic powered human beings, perhaps well meaning at first episodes, included in this list are the inventions and weapons man supposedly created himself: CITY BENEATH THE SEA, THE FEAR MAKERS, THE MIST OF SILENCE, THE PRICE OF DOOM, THE MAGNUS BEAM, THE BLIZZARD MAKERS, HAIL TO THE CHIEF, DOOMSDAY (by the way, notice how some force, be it man himself or some alien or sea driven race wants to create a nuclear holocaust all through out VOYAGE), THE INDESTRUCTIBLE MAN, THE HUMAN COMPUTER, CRADLE OF THE DEEP, THE AMPHIBIANS, THE CREATURE I, THE ENEMIES, THE CONDEMNED, THE CYBORG, LEVIATHAN, THE PEACEMAKER, THE SILENT SABOTEURS (note the goal of some foreign power is usually trying to sabotage space craft efforts as are some alien beings in later episodes--coincidence?), THE X FACTOR, THE MACHINES STRIKE BACK, THE DEADLIEST GAME, GRAVEYARD OF FEAR, THE MENFISH, THE MECHANICAL MAN, and THE DAY THE WORLD ENDED (which like THE PLANT MAN contained a telepathic or mind controlling human enemy). It is interesting to note that the Senator in THE DAY THE WORLD ENDED used stock monsters for his illusions. Monsters that have appeared before in VOYAGE--either taking these terrors from the minds of the Seaview men or...and this is a big or...using monsters of the alien intelligence's knowledge--whether or not the Senator was aware of the aliens behind his powers is another story. The gas on the strange island in NIGHT OF TERROR and the radiation leak in SEALED ORDERS new type of missile caused similar illusions---and monsters appeared again that looked exactly like one another (and a few appeared in LOST IN SPACE as well as VOYAGE---THE THING FROM INNER SPACE, NIGHT OF TERROR, and SEALED ORDERS showed up in LOST's PRISONERS OF SPACE) More in this list of experiments gone mad or wrong: DEATH WATCH, THE PLANT MAN, THE LOST BOMB, THE CREATURE II, NO ESCAPE FROM DEATH (forgive them for crossover but this has a jellyfish with whale innards-type monster), THE WAX MEN (what were the wax men really? And how did the clown--who has no name--create them? Was he human? Were they his creation or the byproducts of some alien masterminds behind it all? Was the clown an alien? Or some alien weapon himself? Or simply a used human?--it must be noted that toys and dolls were used in other episodes that featured aliens attacking Seaview--WAX MEN made no such claim to aliens being behind it but...?), FIRES OF DEATH (which can fall under many categories--mad scientist, supernatural, experimental, alien forces), MAN OF MANY FACES (involving the Moon coming toward the Earth and Nelson mentions that Mason, the scientist didn't realize it would do this--perhaps something else was behind it all--and Mason certainly had agents behind him), FATAL CARGO (so how many white apes have you seen on Earth?--there was one similar one in STAR TREK!), BLOW UP, THE ABOMINABLE SNOWMAN (which overlaps with LOST IN SPACE's monsters in SPACE CIRCUS, REVOLT OF THE ANDROIDS), SECRET OF THE DEEP (with a repeat of many of the monsters across VOYAGE's four years), MAN-BEAST, and THE DEATH CLOCK.
A sub genre of the mad experiments includes time travel and time machines which pop up in TIME LOCK (Alpha in the year 2823), A TIME TO DIE and NO WAY BACK (Mr. Pem in the present of VOYAGE-1981 and 1982). Both humans, Pem and Alpha, didn't seem able to concoct time travel machines on their own--they may have had some push in the right direction or were outwardly helped by aliens or some other more intelligent life form. THE DEATH CLOCK is one of the oddest of the time travel stories where a corpsman, Mallory, has a device that can bend time and change it to alternate realities--a world of tomorrow that can or can't happen. Did the corpsman create this on his own? An island drifting in space and time appears in the sky in THE DEATH CLOCK. It can also be noted that the device is similar to the effects of the missile in SEALED ORDERS and the servo actuator in LAND OF THE GIANTS-THE GRAVEYARD OF FOOLS--where the giant men--aliens themselves--human but alien to Earth--claim "it came from the stars." Are these all linked? It should be noted that supernatural terrors such as those found in HAUNTED SUBMARINE, CAVE OF THE DEAD, RETURN OF BLACKBEARD and others also have the power to stop time or slow it down or make it go back (as do the aliens in DEADLY CLOUD). All similar. Related? While on the subject of LAND OF THE GIANTS--NIGHTMARE in GIANTS had a similar radiation leak to SEALED ORDERS with the same type of illusion causing! In GIANTS, an element on the giant planet caused this. Did the President of the US know something about the silo in SEALED ORDERS he wasn't telling (Nelson even tells Crane that the builders of the silo weren't about to tell him more about it--he didn't have the info on it--which is highly irregular for Nelson not to have info on the missiles--he always did in the past episodes).
In DEADMEN' DOUBLOONS, Captain Brent may have been faking that he was a real reincarnated pirate but in fact, the Capt. Brent in 1524 looked too, too much like the Brent in 1978. Perhaps not reincarnation but maybe it was really the 1524 Brent.
THE MECHANICAL MAN is certainly the creation of a human man or at least the responsibility for his building falls onto Paul Ward but how did Paul get such knowledge to build this being of incredible power when just a year or so earlier THE INDESTRUCTIBLE MAN was just a bucket of bolts which looked very inferior to Peter Omir 50. I realize that perhaps eight years may have gone by from season one to season two but Omir was beyond what we can do in 1997! Who gave Paul this knowledge and what force wanted Omir to conquer the galaxy, not just Earth? A fan fiction story once told of an alien sea race that came from the stars and in it the Seaview encountered a race of amphibians that wanted one of their own back--a girl who was really one of their experiments and their own kind---and the story tried to say the encounters of the Seaview and such menaces weren't all random. In the story was a cameo by Prof. Bernard Quartermass (an England scientist with his own set of adventures--about four or five, and with aliens who were here before).
This is all just food for thought. But maybe you shouldn't think too hard about it all. We wouldn't want you to. Neither would they.