In honor of the great cartoon tie-in to that Godzilla movie that everybody hates finally having a good DVD release (which I found well after it was originally released, because the local Wal-Mart is awful), here's a list talking about some personal favorite monsters.
(Honestly, it's not really a list of the very best or even my very favorite, but a list of ones I consider more notable and worth paying attention to. I left out a few I really like, honestly, like the so-called Thorny Devil, Norzzug the living statue, the Fire Monster, the giant frog/plant hybrid thing that thought it was Swamp Thing, and the giant scorpions.)
Each is listed with its debut episode's title here for your convenience. (Unfortunately, the Godzilla wiki isn't very good about this series, and all the episodes are currently redlinks there.)
10. The Crackler, What Dreams May Come. Okay, honestly this is a little bit of a concession to personal taste.
See, the Crackler barely qualifies as an actual monster, because it's actually a manifestation of the amplified brain waves of an insomnia patient. Calling this thing a monster is like calling a bolt of lightning an animal. And it's made of electricity, somehow, so it's a surprisingly apt comparison. And even by the admittedly often tenuous science of the series, this doesn't really make any sense.
But it has a wonderfully alien design, and I adore it.
9. Crustaceous Rex, New Family: Part 2. Crustaceous Rex kind of had to make this list, being the first proper enemy kaiju to be introduced in the series, and a bit of an icon for it as well, appearing in a number of episodes other than his debut (despite being fairly unambiguously killed by Godzilla).
Unlike a lot of the monsters from the series, there was no real explanation of just what the flip it's supposed to be, because it's definitely in no way a crustacean or anything like one. Instead, it's some vaguely unidentifiable Barlownian beasty that pretty much is entirely alien (a lot like the Crackler, really).
It also eats tar that somehow magically parasitizes other animals and at one point pukes some in Godzilla's face.
C-Rex isn't a particularly formidable monster, honestly, but it's a charming one.
8. Ice borers, Freeze. Okay, these guys weren't originally going to be anywhere near this list, because they're honestly kind of silly little things and not that impressive design-wise. But then I read that they're probably based on an April Fool's gag about naked mole rats burrowing through ice with their super-hot foreheads, and I figured they deserve a spot for that.
Otherwise, they're just big moles living in the Arctic.
7. Sub-Zero Manta, Wedding Bells Blew. Something that's actually a teense lacking in Godzilla: The Series is kaiju with iconic profiles. A lot of them are just huge animals or incredibly weird things, and don't quite have the same punch.
And then there's this thing, a completely inexplicable thing that resembles a giant manta ray that flies, only breathes air, has an icy breath weapon, and repeatedly attacks buildings with good air conditioning because it's trying to find a place to hibernate.
Easily my favorite part of this particular monster was that when it got into an inevitable breath weapon war with Godzilla, it was as if the two monsters were clashing weather fronts and started causing severe storm weather to manifest.
6. The Shrewster, The Twister. And then there's the gigantic rodent created by nuclear power/wind power experiments (seriously) that merged with and controlled a tornado.
I love the Shrewster for no reason beyond the fact that it's a giant animal that's merged with a weather pattern. That is golden.
(There's also the fact that its incredibly high metabolism is a loosely implied explanation for how a tornado can be sustained for weeks, which actually makes a minute amount of sense.)
5. Bacillus, What A Long, Strange Trip It's Been. It's kind of funny that there's a monster that's supposed to be just a big old bacterium.
It doesn't make any sense, and it's honestly part of one of the sillier episodes (one of those "journey through a living body" plots that honestly aren't very good), but I really like its design.
4. Quetzalcoatl, Bird of Paradise. Sometimes your giant monster cartoon just needs a giant ugly firebreathing birdosaur.
While it looks surprisingly like a hoatzin, which is a neat bit of trivia (hoatzins are South American birds and the only living member of a big family of birds, and the only birds alive today which at any point in their life cycles have true claws on their wings), it's vaguely implied that "Q" may simply be a big, weird holdover from prehistoric times rather than a mutant like most of the other monsters of the series.
3. El Gusano Gigante ("the giant worm"), D.O.A.. El Gusano, as he's often known for short, is one of the more massive monsters from Godzilla: The Series, at least by bulk, and that gives him a lot of presence; he's one of the more iconic monsters from the series, and like C-Rex appears in several episodes.
While he has some superficial resemblance to both whales and armored dinosaurs, looking at his anatomy he's almost certainly some kind of weird Onychophoran, that is, an offshoot of velvet worm.
Also like C-Rex, his primary role in the series is getting stomped on by other kaiju, because despite his size he's a pushover, though he definitely lived through his run-in with Godzilla. (The only reason he was a serious threat to Godzilla is because he was immune to the toxin that the local government tried to kill both monsters with, and even got a little more impressive because it was a concentrated form of stuff he ate.)
2. The Techno-Sentient, Juggernaut. The Techno-Sentient is both one of the most inexplicable* and one of the most terrifying monsters to appear in the series.
First off, it was able to absorb technology into its body almost completely at will, to the point where missiles that hit it didn't detonate because it had already subverted them; this made it only a little shy of indestructible.
Second, while it was pretty alien, it was very intelligent, and figured out from data it had downloaded from the internet how to start a nuclear war, and promptly tried to do so by invading a missile base and launching a missile at Baghdad. (Fortunately, its own plot was its undoing, because it got stuck to the missile and the missile detonated in orbit instead of when it hit its target; that was probably the only way to stop the darned thing.)
It was easily the most threatening and dangerous monster to appear in the series, and there was no explanation of its origins beyond "it fell from space" and no explanation of its motivations beyond "it wants to kill all organic life on Earth."
*Someone on the wiki suggested, and not without reason, that the Techno-Sentient was a creation of the series' aliens, the Tachyons**. While it makes some sense, I have to admit I don't really like the idea, because the Techno-Sentient was much more effective story-wise as something thoroughly inexplicable.
Also, 1) I think they'd have noticed similarities between it and the technology they'd already observed and worked with if it was made by the Tachyons, and 2) it would have spent less time screwing around than it did if it was on a mission it had been sent on; it would have had better intelligence if it had been sent by somebody who'd been to Earth before it.
**I don't really like that name as the name of an alien race, but ah well.
1. Skeetera, S.C.A.L.E.. Skeetera is the sort-of star kaiju of what is easily the best episode of the series. S.C.A.L.E. used an experimental storytelling style by framing the episode as a documentary composed from camera footage, something like what Cloverfield was trying to do but more successful (well, I suppose not that much like Cloverfield, but the point stands), and was a much more interesting narrative to boot. In fact, I'd say it was better than just about every "artsy" movie I've ever seen.
But enough about that; Skeetera is the hands-down best kaiju from Godzilla: The Series because she's perfect.
First, she's the only monster whose name would fit in in the wider Toho canon, even if it's a name that Toho probably would never quite have generated themselves. Compare it to "Mothra," for instance.
Second, she's probably the most iconic monster in the series (GIANT KILLER MOSQUITO), and iconic in a way more akin to the recurring Toho monsters. (I hate to harp on comparing her to Mothra, but she's really got a lot in common with the other female insect kaiju, except she's rather more evil, or at least amoral.) But she still fits in with the series' own feel.
Third, she has a neat power that's derived from her animal inspiration (sucks blood of other kaiju -> gets bigger and gains new powers derived from victims) in an intuitive/magical thinking sort of way. (Which, with Mothra's "poison dust" attacks being derived from the same sort of thinking, is yet another thing she has in common with her.)
Skeetera only showed up in this one episode, but she's so iconic that I was a bit mystified when Matt Frank left her out of his excellent art-based fan series, Godzilla Neo. Out of the things in this series that need more love, Skeetera is definitely the most deserving.