I love how even from the way her tail tapers down and mimics a forced perspective, you can kind of tell that Onix is meant to be enormous, to the tune of thirty feet long (sometimes looking even bigger depending on the artist). The species doesn’t even evolve from a smaller rock Pokémon to get there – they just start huge and stay huge.
Even more than the Pokémon literally named “Golem“, this seems like an animated set of boulders – not even any limbs to speak of. Being made of solid rock definitely helps make her feel gigantic and solid, too – everything about Onix is just satisfyingly hefty, while her face feels more “immovable object” than “unstoppable force”. The best feature of the design, though? That dorsal fin on her head, which presumably is used as a rudder to help steer as she burrows through the ground. Lovely little functional feature on what’s otherwise one of the more monster-y Pocket Monsters. She’s not complicated in her design, but everything that’s there just works.
Take the already-intimidating Onix, coat it in cold hard iron, and you get the older- and meaner-looking Steelix! She feels a lot more textured and craggy now, and the fins being along its body give the idea that she can more fully steer herself with the burrowing equivalent of “wings” rather than being purely snakelike. That spike on her tail is just the icing on the cake, since she already looks like a colossus that could crush you effortlessly. Her proportions are a little weird – the oversized, powerful chin in particular – but that feels like part of her charm and emphasizes the sheer scale of her. This is a great progression of a classic Pokémon, and another of my personal favorites.
Steelix is obviously crazy-defensive, what with being iron-plated and all, plus she has a ton of type resistances and immunities. She’s a bit of a hammer, though – a few really strong, simplistic attack options with good attack stat, but little else that she can really do and some problems with speed and resisting certain types of attacks. Still, she’s pretty sturdy and good at a straightforward hitting-things strategy, which a lot of the time is just what you want.
Onix was the most physically imposing Pokémon early on based on its massive size alone, so he got a lot of attention as one of the more monstrous Pocket Monsters – and that’s kind of lingered since, so she’s got a lot of visibility. Meanwhile, Steelix is so synonymous with the Steel-type that every Steel-type Gym Leader in the series so far uses one on their team, which is some serious pull.
While Onix may be pretty straightforward as a rock-snake, the fact that they’re so huge means that their digging leaves behind tunnels large enough that other Pokémon can live in them. It’s never been said outright, but the fact that such large creatures are found almost entirely in cave systems implies that burrowing Onix are a major way in which caves get formed in the first place (and why there are so many easily-traversible caves in the series).
There are actually a few variations on Onix out there, considering that their hides are mostly made of accumulated material much in the same way that Alolan Graveler picks up detritus as it rolls downhill. A singular Onix is shown made of a crystalline material, and supposedly it’s common for them to grow smooth and blackened with age as they get battered and harden. It’s nothing that the games ever reflect, though, which is a shame.
In fact, how Onix even works is also never made particularly clear. It has a brain, and can eat and digest soil, which suggest there’s something organic going on – on the other hand, there’s a magnet embedded in the brain and not much connective tissue between the boulders, which suggest that at something more akin to living rock. Kind of a head-scratcher, but she looks cool, so whatever, I guess?
A lot of the text around Steelix claims that this is actually one of the aged, harder forms of Onix, being compressed by the sheer weight of the earth and heat of its core into something more diamond-like. Unfortunately, that directly argues with the fact that you evolve her with an item called “Metal Coat” – and, y’know, steel being right there in its name. The other running explanation is that after eating enough iron scraps over time, she develops something of an iron shell as she evolves. Maybe the pressure of the former triggers the biological reaction of the latter?
There’s tons of fun be had with Onix and Steelix just as superlatives, though – aside the whale and a certain walking joke introduced later, they’re the biggest non-legendary Pokémon around, live deeper underground than any land-dwelling monster (by a whole vertical kilometer), and have nearly the highest natural defense in the game. But to balance that out, let’s remember that every Pokémon has a favorite spot where they like to be petted and scratched – Steelix’s is the jowls about the base of its head. Just imagine something of that size, purring contentedly, shaking the very ground beneath it by sheer force of happiness. Adorable.
Onix is a classic, and Steelix builds on him wonderfully in such a way that nothing has really challenged their role in the position as “big ole mountain monster”. These two feel like Must-Haves for the series long-term.
Any and all appreciation for Onix and Steelix is welcome in the comments!