...the Void in the concoction seems to overwhelm any regenerative property given by the potion itself, rapidly overwhelming the transformation and destroying first the soft tissues and then the chitin of the subject before the change can fully take hold. Though the subject seems to live, still, they do not display any of the solidity in form shown in the subjects samples were taken from, and do not seem to be capable of keeping a consistent form. Short-term, I'll be keeping her in one of the tanks out back. Once all of this is over, I'll see if the Void within her remains viable for potions, and check if there are any potential buyers...

Aurelia from @subwaybug is a vessel - meant to be one, at least. Just a bit of a wrong balance, and something goes... off. Shifting flesh eats into shell, consuming chitin in mottled, stained chunks rather than smoothly integrating. Fur falls out in ratty chunks, shrivelling to dust before it reaches the ground, pale wood showing where shell once was. Some key component of the spell leaps to life, consuming the host's body and then the very guidance of the spell itself, eating the bee from the inside out. That which has been done can no longer be reversed.

The error, in this case, is server-side - a fundamental misunderstanding on Marigold's end of what, exactly, she was working with.

The thing about void, its primary property, is that it is a concentrated essence of nothingness. The total absence of anything - sensory deprivation in a bottle, an absence distilled down to its core. When properly activated, that absence becomes hunger - eating away at its vessel as much as that which is trapped within it. Though the shell of a god - say, the White Lady or Pale King - can resist it and provide a hull for a newly-formed void creature to inhabit, mortal bug's shell doesn't have the same resistance, and the transmutation can only affect so much before the void's hunger outruns its ability to transform.

In this case, what you end up with is an immature void creature - a form barely defined enough to survive on the surface, and some marked difficulty with keeping things like claws solid enough to interact with the world around it. Tough luck! If you shunt her into the Abyss, she'll probably be able to actually interact with the outside world in a decade or so, but we really don't think that this one is reversible, not with the current nature of her body.

...I honestly don't know what went wrong! That potion shouldn't have been capable of producing those results, and something like this should have been impossible to make happen at all with those ingredients. All I can think of is if their magic messed with the formula somehow, or if they somehow catalyzed something new entirely. The wasp's charm worked perfectly fine! I don't know why another fungus would react so differently. It's too aggressive to study further, not without help, and I don't think I can gain more from the spell weave. I think I'll have to call in the Explorer's Association to put it down...

Fulminis from @motheatencrow, on the other hand, is... something else. Something between a Corpse Crawler and a Charged Lumafly Swarm, pieces of shell breaking off into brilliant, glowing lumaflies as chitin creaks and breaks into new legs, something that shouldn't exist, something that should not exist - but that exists anyways.

The error in this case is client-side - unpredictable reactions in the subject causing odd reactions in the formula. Fun fact: one of the most common activating catalysts in Marigold's brews is powdered crystal, giving the spell web the power it needs while retaining the freedom of form. With Fulminis, the electric crystals already present in cir body interfered with the process partway through, throwing off the transmutation in a major way and causing, well... a half-done transmutation into two things.

This one... look, we'll be honest here, we don't know how well this is going to work out in the long run. With a consciousness split between dozens of charged lumaflies and a corse crawler body split open to show cir insides, there are really gonna be some limits with what ce can do with this. Though this might be technically reversible, it'll be a hell of a task - it's two transmutations in one, each tangled in a way that might very well make it impossible to undo without making the other one go haywire in a particularly bad way. It's an adventure at best and a nightmare at worst, and that body can't be comfortable...