Since Malaconda is Dark/Grass, pure Grass doesn't really fit. Normal/Grass is definitely an option, though, and probably the best choice if we want little Malaconda to be an uncorrupted version of its bigger self.
Honestly, I think everyone loves to overthink these things. How many times do pokemon change types upon evolution? A small percentage, thats how much. No need to get too symbolic with things. Every idea people have thrown around can be as easily done with the existing type as with any other, and any difference that would come about from dropping a type or replacing one with Normal (ugh) can just as easily be portrayed with Dark/Grass.
The only other real types that I think stands out as being reasonable is Poison/Grass or Dark/Poison. Personally I think the latter is better, but either would be OK. Now, obviously the movepool would be odd for that, but it is a reasonable change flavor-wise, and unlike dropping a type or trying to sub in Normal it actually represents something completely different than Dark/Grass. There is also the Skorupi/Drapion line that can be used as precedent, as it changes one type drastically upon evolution to one of the types we have here.
As a side note, can we please stop bringing up normal/something all the time. Normal adds nothing to flavor, so unless we want to be pure Normal, there is never a reason to have it at all. Something like pure Grass to Grass/Dark has the exact same implications as Grass/Normal to Grass Dark, and has much, much, more precedent. Being unique for its own sake is just silly and ridiculous.
This is a 12 hour warning for the Typing Discussion.
If discussion really heats up and it's obvious that more time is required for all ideas to be adequately presented, then the discussion will be extended, though most likely not beyond an extra 12 hours. Otherwise, expect to see the thread closed after twelve hours have passed. That time is around 3 PM CST/8 PM GMT.
If I am not able to close the thread at that time (as a result of not being at my computer), I guess consider that a temporary extension? It's like stoppage time in a soccer football match. It'll end when the referee wants it to end.
Feel free to discuss whatever typings you can think of. Who knows, maybe your ideas will gain a lot of traction!
I think that Grass/Dark would be the best option in terms of flavor. I just can't ever see Malaconda as not being a Dark type Pokemon in its life. Being once uncorrupted does sound nice, but I really can't see a Malaconda pre-evo being anything else but Grass/Dark as well.
From all the options stated so far, Dark/Grass sounds like the best preference. Grass is mostly an innocent/nature based type- even Cacnea/Seedot start out as this before going to the dark side, so to speak. It would be nice to be different and have a pre-evo that has this Dark nature at the start.
Alternatively, how about just a Dark type? I'm aware the Egg Moves list has some Grass-related moves in Aromatherapy, Sweet Scent, Stun Spore and Poisonpowder but what if this pre-evo is like Sudowoodo were it's faux-Grass type at first? What about a story about a little snake that mimics Grass-like attributes to disguise itself before evolving to the Malaconda that actually gains a Grass type and the Harvest ability to become self-sufficient in terms of luring prey?
In that case though, it will have to lose the very obvious moves of Leaf Blade and possibly Vine Whip in its movepool (Power Whip maaaaybe okay, ala Lickitung). Vine Whip may have to be replaced by something like Constrict, nothing game-changing. As for the Egg moves, you don't need to have actual grass features to use them unlike Leaf Blade:
- Blissey gets Aromatherapy, maybe pre-evo can release pheromones that mimic fruits?
- Similar argument with Sweet Scent. Back when it was a TM you didn't have to be Grass type to learn it.
- Poisonpowder maybe a bit trickier, but its not actually a Grass move anyway. Maybe it's snake features (usually linked to poison) combined with the 'trying to be a plant' thing may be combined to justify that. Then again, Butterfree/Mothim learn Poisonpowder and they're neither Poison or Grass.
- Stun Spore has a similar argument to Butterfree/Mothim/Masquerain. I just like to think it has features that mimic plants are on its way to becoming a Grass type but they're not fully realised until it evolves and gains the Harvest ability.
tl;dr- a Dark faux-Grass mini snake trying to lure prey evolving to actually become the Dark/Grass after gaining Harvest to actually make its own fruit lures.
Myth-wise it could be the snake gaining knowledge to evolve to this creature who is now an expert in temptation and will be more connected to the idea of the Garden of Eden snake.
What about the normal typing adds the "idea of innocence" any better than just making the prevo pure grass? Looking at a list of every normal type, the normal typing is almost explicitly used as a typing for mammal-esque, bird, and transformation pokemon. A small grass type snake, which is what I'm assuming the prevo will be, just doesn't fit.
I think Pure Grass is the most fitting. Pure Dark could work too, I imagine some shadowy figure still in an egg.
Okay, it looks like we have a consensus as to which types the community wants. It's been about 36 hours since the discussion began and the same ideas are beginning to circulate, so this is as good a time as any to shut this thread down and move on to some polls!
Thank you all for a great discussion. Four different types have gotten significant positive responses from the crowd, so those four types and type combinations will be moving on to the poll stage. Those four typings are (in no particular order)...
Grass Dark/Grass Normal/Grass Dark
I am currently away from my computer and cannot post the poll right now (I am writing this post from a phone), so hold tight and I will create a poll thread in a couple hours. Thank you to everyone who participated in this discussion and everyone who talked on IRC about Malaconda's pre-evolution. Let's hope every other step runs as smoothly as this one!
EDIT: Forgot that Dark is the primary typing of Malaconda so the dual-type options should be switched. The post has been edited to adjust to these changes. Instead of Grass/Dark and Grass/Normal, the slate should include Dark/Grass and Normal/Grass.