If one grows attached to an individual Grimmsnarl raised in captivity from a young age, is it possible prevent it from collapsing and splitting into Hatennas (thus living out its whole lifespan as Impidimp/Morgrem/Grimmsnarl)? Perhaps through using the same principle by which Everstones* work? (*Probably hormones)
In fact as Grimmsnarl fan who's even more of a Morgrem fan, I would be interested in how everstones/evolution blocking works in this setting in general, if such a thing is possible.
Excellent questions, Anon!
I have good and bad news for you. Good news: there is a chance your Grimmsnarl will not devolve / collapse into a cluster of Hatenna! Bad news is that there's no known way to definitively influence whether or not that happens. If it doesn't happen, it means your Grimmsnarl passed without fully completing its lifecycle. However, if you own a silver (shiny) Grimmsnarl, your Pokemon will devolve directly into Hatterene instead. Whether or not this would be "desirable" over a Hatenna cluster really depends on who you ask. On the flip side, a silver-devolved Hatterene will remember you as its trainer, while the Hatenna cluster will not. An Everstone would be of no help here, as the evolutionary stones and stone-based and equivalent evolution / development operates around radiation and / or environmental exposure in this setting, and an Everstone would act in equivalency to a radiation nullifier. ***Evo stones and similar items are in a state of flux for this project - evo stone and item-based evolutions are a bit of a case-by-case thing at the moment, but this is the broad strokes.
The when and how of Grimmsnarl collapse into Hatenna is both highly variable and clear as mud. In terms of "when", the timeline for how long a Grimmsnarl will live as a Grimmsnarl before it undergoes Hatenna collapse is estimated to be as short as eight years to as a long as thirty. The process of "how" is very murky and not well understood at all - clarity on the subject requires recognising and studying the degradation period of the final stages of the Grimmsnarl lifecycle. In terms of recognising degradation, there is, at minimum, a link of some kind between the degeneration rate of a Grimmsnarl from entering adulthood to collapse, and individual fertility: once a Grimmsnarl stops producing Witches' Hair (re: approximately 35% minimum of its pelt has turned white), it is firmly on the road to collapse. How much correlation versus causation is present, if any, in this proposed link is unknown and would need much more research. Regarding that research, few are willing to perform it; it is considered both very unsafe, as Grimmsnarl that are nearing collapse retreat deeper into the wood where Hatterene dwell, and in direct conflict with conservation efforts, as any process of evaluation would be - at this stage of research - invasive, which puts the target Pokemon itself and the possible future Hatenna at risk.
However! Good news is there may be an option for you as a trainer to prolong your Pokemon's life! There is a theory that diet can influence speed of degeneration, and that an altered, psionic-lite diet can extend your Grimmsnarl's life as a Grimmsnarl once degeneration starts. Limited research that has been done so far has hypothesised that Hattena develop from a Grimmsnarl's psionic glut - a semi-viscous, semi-fibrous material that runs parallel to / is entwined with the core nervous system. Psionic glut is present in large, measurable / observable quantities all dark-, psychic-, and ghost-types, and is believed to be what permits psiovorism, extremely strong psionic broadcasting and / or blocking, and self-orientation within multiple dimensions in a Pokemon's sensorium. Since Grimmsnarl is a facultative, negative- / depressor-wave psiovore, and Hattena is, more or less, an embodiment of negative psionics, the theory is that moving a Grimmsnarl to a primarily solid / liquid diet over psiovorism will hamper Hattena development. More than behavioural training would be needed for this shift, however, as receiving psychic broadcasts is roughly the equivalent to "grazing" for a psiovore, and a Grimmsnarl's natural propensity for being an irritating, aggressive shitlord will mean that negative broadcasts will be around it fairly consistently, ready to be eaten. Not only would you need to behaviourally train your Grimmsnarl against cultivating negativity around it, you'll need to train it to ignore its natural feeding impulses, and / or feed it / give it psychic scramblers / blockers to disrupt its ability to feed on these broadcasts in general. Fair warning: this will make your Grimmsnarl unhappy, since these will impact the glut and make it feel generally out-of-sorts. If you try this option, you'll need to keep an eye on your Pokemon for the first leg of the dietary transition, as there is a good chance your Grimmsnarl will start stepping in circles or walking directly into walls due to its sensorium being thrown out of whack depending on what you gave it. Emotionally, your Grimmsnarl will be confused and generally pissed off for a bit - give it some reassurance and feed it some of its favourite solid / liquid foods to help it adjust. If you're a battling trainer, keep your Pokemon out of battle until it fully adjusts and adapts, otherwise you're going to risk some severe spooking in the arena. If you're a working trainer and your Grimmsnarl is a working Pokemon, it should be put on leave until it adjusts / adapts for similar reasons.
How much of an effect this should theoretically have is somewhat dependant on genetics, which you can partially measure yourself by looking at how quickly your Grimmsnarl began turning white. If it started sprouting white strands early (within four years of reaching adulthood, ballpark) then you're most likely saddled with a really poor genetic draw, or the environment you're living in is exceptionally physically or psionically toxic to your companion - or both! However, if your Grimmsnarl is comfortably outside of that early collapse window, you'll possibly be able to keep your Pokemon out of the collapse zone for a while longer than normal.
Final batch of bad news: your hand-raised Morgrem will become a Grimmsnarl, and you'll have very little say in the matter. For the grand majority of species, "evolution" is translated literally as natural physiological development from infant > [+/- juvenile >] adult in this setting. Often, three-stage species will be considered "adults" when they reach stage 2, with stage 3 being a further development within adulthood. Stage 1 and Baby stages are considered across the board to be "infants" / babies, and that stage is always temporary - growth to Stage 2 is guaranteed regardless of what you do with your Pokemon. Single-stage Pokemon look largely the same throughout development - their babies are just smaller and more intensely fuzzy versions of their adult selves (like a kitten or puppy versus an adult cat or dog). In species that possess a Stage 3, prevention (or even encouragement) of post-maturation varies, and would likely involve environmental and hormonal alterations. Stress is a big factor in an already-adult Pokemon undergoing post-maturity development.
For the Grimmsnarl species, both Impidimp and Morgrem are formally classified as "infants", and will grow into a Grimmsnarl, guaranteed (a Morgrem isn't considered a "juvenile" until a specific growth milestone is reached, whereafter it will "explode" into an adult within 8 - 12 months). The only control you'll theoretically have over your Morgrem's growth would be its environment. If it's raised in an environment where other members of its species are present, or it is surrounded by species that have developed a resistance to its parasitic lifecycle, it will develop at the expected, normal pace for the species: by the time the Pokemon reaches about the age of six or eight, you will have a Grimmsnarl. However, if you raised your Morgrem in an environment where there are no other members of its species, and the other species around it has no established resistance to its parasitic lifecycle, your Pokemon will be a Grimmsnarl - an extremely aggressive one at that - on the shorter side of two years.
I hope this answered your questions, Anon! Please have a Morgrem for your trouble:
This is Vance's silver (shiny) Morgrem, Harry, enjoying a rabuta-glazed doughnut - his favourite.
