Right, after hearing about and trying out Mollux in a lot of scenarios, I believe now is the time to give my final thoughts:
In short, Mollux can be described as a square peg in a round hole.
First of all, while Mollux has a lot of options at its disposal, it tends to have to heavily segment itself into parts. This is a consequence of its awkward stat spread. As a result, once you see one, sometimes two tops, moves of a Mollux's moveset, you will 9 times out of 10 know exactly what Mollux is running. This is unfortunate as Mollux really requires the opponent
not knowing what it is to do its job.
STATS
To further understand Mollux's issues, we have to delve into its stats. First thing's first: Speed. My god, we could not have given this thing a more awkward speed. Quite frankly, this ties in with ability. We should not have given it stats until after the secondary ability polls, as this speed was clearly designed with drought in mind. Using RD's ideal EVs of 248 HP / 88 SpA / 172 SpE Modest, we can kill steel/grass types with lava plume, sure...but that leaves it outclassed by Magnezone utterly. So, really, 76 speed just shoots it in the foot for the roles it excels at, as it's too fast for trick room while too slow for any speed investment without scarf. Mollux is, unless running the rare scarf set, going to run last. I'll go back to why this is a problem in a minute.
Its defensive stats are...well, they work. Makes it go up against bulky waters with ease, which is what it mostly wants to do. Can survive one sassy Ttar stone edge at max HP, but don't expect it to take physical non-fighting/grass hits without investment.
131 SpAtk wrecks faces, but is crippled by the speed. It can run a scarf set, but it's outclassed. More on that in a bit.
ABILITY
Hardcounters bulky waters and spins in the rain. Use Illuminate on scarfed sun sets. Niche usage: Water soaker on sand teams. Sun teams already have chlorophyll so not as important, plus dry skin hurts in the sun.
MOVEPOOL
Rapid Spin + Recover + Protect / Stealth Rock / Toxic Spikes + Attack under the rain.
This is all Mollux can feasibly run in a nutshell. I don't mean that simply because it's the best set Mollux has, I mean it because Mollux has no setup moves that work, simply because of its EdgeQuake weakness. Look at all the common setup sweepers in OU, and you'll see a common trend - either they have typings that lack horrible weaknesses, which let them set up repeatedly, or they have a way to boost their speed at the same time as their other stats.
The movepool itself has many options, it's just that Mollux is outclassed in almost every roll.
TYING IT ALL TOGETHER
Mollux had a really, really good chance here to be an offensive presence as well as a defensive presence to help migate its x2 and x4 weaknesses, as suddenly it can beat common switchins with a surprise agility! But no, all it has is calm mind, and the ease of which ground and rock types/attackers come in on it means that it can't do shit and has to swap out. In addition, its taking a full quarter of health every time it switches in, so it can't try many times to set up. This makes it automatically inferior in every aspect to every other setup sweeper, as it doesn't have the resistances to pull off a bulky setup, nor the speed to pull off a one turn setup. Plus, although dry skin recovery is nice, fire, its main attacking STAB (lol poison) gets cut in half by the rain.
Can it run a scarf set? Maybe. But if you look at the likes of other scarf users, such as Terrakion and Salamence, you'll see they have high speed and overwhelming offenses, as well as diverse movepools. Mollux has a low enough speed that it cannot properly outspeed and revenge many common +1 spe sweepers, and crappy enough defenses that Blissey and friends just stop it cold. Not to mention its (lack of) coverage, making it even more ill suited to the job of a scarfer. In addition, it requires an inordinate ammount of prediction, as being locked into the wrong move spells your doom. In summary: Outclassed
Can it run a specs set? No. It does not have the coverage, and it is too slow. It is also outclassed by other bulkier specs users. It might work in trick room, but then blissey the fat whore comes in and ruins your day. Or airloon heatran. Plus there's the problem of trick room being painful to set up.
Can it run a Cleric set? No, it has nothing that a cleric wants.
So what can it run?
Tentacruel's set. Mollux is, pretty much, Tentacruel 2.0.
SUMMARY
You'll notice outclassed pops up a lot here. That's because that's what Mollux is. For all the toys he get, he can't really use them. He's too slow and lacks the coverage to use scarf, too predictable and slow to use specs, too squishy, weak, and predictable to use life orb...
Which leaves him with a spin, recover, attack, hazard set to use. Which, while great, is...pretty much all he can do.
So uh, if you want to know what Mollux can and cannot do, just imagine a better Tentacruel with fire instead of water typing. We...didn't really create anything new here. I appologize if this seems like it ran out of steam at the end, but...
well...
it's tentacruel.
tl;dr
=
but better.
