The claim to fame of Poliwag is that it is Pokemon creator Satoshi Tajiri's favourite pokemon. And that means it should also be YOUR favourite pokemon.
If you haven't read up on this guy and the early days of Game Freak, it's an incredibly do-it-yourself, inspirational story. Game Freak was so broke during the first game's six-year development that five employees quit and Tajiri stopped paying himself a salary. At all stages there was doubt it would be published; when it finally was, it had a really slow start, and only started spreading through the appeal of the link cable. In a way, it was the precursor to online games.
It's easy to take Pokemon for granted now, but we wouldn't be sitting here enjoying it if it weren't for this one person and his keenly sensitive relationship to the world around him. Even something as singular and nostalgic as spreading honey on tree bark to catch beetles—that made it directly into the games, as anyone who's tried to catch Heracross in D/P can attest. Not many games and media franchises are based on specific childhood experiences like that.
Usually we have to sort of speculate about pokemon origins, but Poliwag comes directly from Tajiri's brain: “It looks like a tadpole. There's little whirls on it because I remembered that when you pick up a tadpole, you can see its intestines because it's transparent.” Okay, so that's not the most elaborate origin, but it's simple and original. The “I remembered” part is the key; it's not “what do people remember about tadpoles,” it's “what do I remember,” and in this case it's little Satoshi Tajiri holding a pollywog in his hand and going “woahhh, I can see through its skin!” For whatever reason, personal touches like that are lovely, and Generation 1 was probably full of them.
Unexpectedly, Poliwag really is a subtle and accurate portrayal of tadpoles. If you're thinking, “What about its googly eyes and rudimentary feet,” well guess what TADPOLES HAVE THOSE SOMETIMES
I mean, look at those. If you transpose their mouths onto their backs and swing the tails around, they would look exactly like Poliwag.
And if you're still skeptical about Poliwag being two feet tall and weighing 25 pounds, bullfrog tadpoles look like they could probably get that big:
If the above picture makes you remark, “gross,” then you are not alone. Tadpoles creep me the heck out. They're dark and slimy and shaped like sperm. They look like snot. And because frogs and toads are often the first animals to show ill-effects from pollution, and tadpoles are the first form of frogs and toads, you're probably more likely to look at a tadpole than any other creature and see something freaky like two heads or extra limbs. Something so embryonic and biologically simple should not be so visible! Nature needs to keep its awkward baby business away from prying eyes, like usual, not all up in our swimming holes. Not that I would trust swimming holes anyway, because that's where brain-eating amoebae live.
But it's easy to see why tadpoles are so intriguing to people. For one, they're widely available; the Common Toad, Bufo bufo, has a range spanning three continents. For another, they have a drastic, visible metamorphosis; they develop not only limbs but lungs post-natally, and completely change habitats; unlike insects that morph in cocoons, we can see all their in-between stages; and finally, tadpoles are pretty much self-sufficient; some walk around on land; some are omnivorous and eat other tadpoles. And I mean, look at that bullfrog tadpole up there. That is a fish. Not bad for what is basically a larval stage. This is the kind of stuff that would make primitive cultures think frogs and tadpoles were unrelated or some kind of godly voodoo was responsible, like maggots being born from rotting meat. Of course, now we know tadpoles metamorphose when they gain enough experience points and reach level 25.
The whole growing legs and moving onto the land thing also neatly parallels the evolution of terrestrial life in general, as every Evolution of Man montage will show us. And where would the Pokemon game mechanic be without evolution?
For all those heavy implications and unsettling qualities of tadpoles, though, you have to admire Game Freak for condensing them down to palatable ol' Poliwag. It used to look a bit more dark, as we can see in its early sprites and Pokemon Pinball appearance:
Diamond and Pearl
I like representations of Poliwag that give it a vaguely pointy shape, like actual tadpole and frog heads. Sugimori's artwork is usually good at this. For some reason that egg shape is just more believable than a circle with feet. D/P doesn't do this as well as B/W and HG/SS, but it's still better than the circular Silver and Crystal sprites. It also has the biggest watery puppy dog eyes and is posed the most swimmingly.
I really wanted to like HG/SS's sprite, but it's kind of asymmetrical in its lower half, like it's missing a butt. Observe how its right eye is higher than its left eye, but its right edge is lower than its left edge!
This may seem like nitpicking, but I stared at this sprite a long time and at no point did that stop bothering me.
There's also the question of how many times Poliwag's guts should spiral. 2-3 revolutions seems to be ideal. But with Crystal through FR/LG, those intestines barely make it around once! LAZY. How are those supposed to hypnotise anyone?
Finally because Poliwag's head is basically its entire body, it contributes to some of my favourite pokemon fusions. Like Squirtwag and Vulwag here.