#feel free to comment theories and ideas too theorizing is nothing without discussion and debate

[nexus-nebulae]

whenever i see hollow knight theorists talk about the grubs i almost never see anyone mention certain things that i always think about so i'm just gonna infodump and see if these theories make any sense? I'm going to be such a nerd about taxonomy and real-life bugs. also note that i haven't genuinely studied this shit in school, i am running purely on wikipedia and Autism™

First things first: they're grubs. They're larvae. They're not finished growing, and as we see from the charm they give, they metamorphose into some form of flying being. It's not clear what, but if the Elegy charm in any way resembles what a Grubberfly actually looks like, then they would seem to have multiple wings and a thick, tapered body (with no apparent legs). We also know that the process of being eaten by the Grubfather involves some form of metamorphosis- either of the Grubs, or even the Grubfather itself. You can even hear them making noise within Grubfather, meaning they're not dead (yet. we don't know if they Will Be Eventually).

most of the time "grub" refers to beetle larvae, but... moth larvae can look pretty similar. grubs and caterpillars are often mistaken for one another. the main thing that gets me is the legs- the legs of the caterpillar are typically a lot thicker and better for movement. whereas most grubs have thinner, typically segmented legs and often can barely even move around with them. We see the grubs in hallownest with relatively thick legs- most other bugs in hallownest just get black lines for legs- and they're able to move incredibly freely.

Now- there's a lot of types of bugs in hallownest, which means a large variety of larval stages. We've got moths, obviously, which are caterpillars. We've got mantises, which have no larval stage and instead hatch directly into nymphs (So, the Mantis Youth enemy is likely a nymph). Baldurs are like woodlice, or isopods, meaning intstead of larvae they have manca, which essentially look just like tiny versions of the adult (e.g., the regular Baldur compared to the Elder Baldur). Bee larvae are simple white grubs, which are typically sealed inside of the surrounding honeycomb until they metamorphose. Spiders hatch as spiderlings, which we see plenty of in-game (and, before the Lifeblood update, Deeplings would even actually pop out of eggs when broken).

We have flukes, which seem to moreso resemble maggots, or fly larvae. The tiny flukes we see at the entrance to Flukemarm are clearly the youngest of the larvae (despite the Flukefey being labeled as such in the Hunter's Journal- the larvae in the walls aren't considered an enemy type in the Journal, however, so were likely not considered). Despite the fact that the Flukes more often resemble worms, we know they are not, as some varieties have legs or wings. Annelids (true worms, like earthworms, leeches, etc) never have legs, much less wings. Meaning the flukes are most likely arthropods, and thus most likely are something close to flies.

And then we have creatures that are in completely different phylums to arthropods, such as the jellyfish (cniderians), snails and slugs (molluscs), and mushrooms (fungi. not even in the animalia kingdom).

But by far the most common type of bug in Hallownest are beetles. Beetles are some of the most diverse insects on the planet even in real life, and in Hallownest it's no exception. We see plenty of beetles based on real life- Dung Defender being a dung beetle, the Nailsmith being a rhinoceros beetle, Willoh being a giraffe weevil. Most other insects in hallownest mostly resemble beetles than other insects, with hard, plated shells and often visible elytra (the hard shell casing that covers the wings). Because beetles are so abundant, and because most other insect species in the game tend to keep within their own separated groups, "grub" most likely became the colloquial form of "baby" within Hallownest. Therefore, these Grubs might not even be grubs at all, but another form of insect larvae that was labeled as grub due to its similarity to beetle young.

We never see any direct inclusions of the young of the Moth Tribe nor the various beetles found around hallownest. There is only a single known caterpillar seen in-game, and that is Marmu. It is not known if she is connected to the Moth Tribe or not, however Marmu's design was based on a Puss Moth caterpillar, of which the real-world equivalent grow up to be similarly fluffy moths to the ones seen in the Moth Tribe. The visual similarity between Marmu and the Grubs is striking- and they even sound remarkably similar, meaning they could be of related species.

Now, back to actual Hollow Knight Lore™:

We know that the Collector is definitely related to the Kingsmoulds, as they are both made of void and have the same body template. All Moulds were made as servants to the king, and do not seem to have their own motivations or interests. The Collector, however, definitely has a personality, ranting and raving about how much it loves the Grubs.

The corpse holding the Love Key in Queen's Gardens is a Husk Dandy, or one of the high elite of Hallownest. It was clearly a high-ranking member of society, and may have had some connections with Lurien, or even the Pale King himself. The Tower of Love was most likely this Dandy's tower, and it was likely the one who began the collection of grubs, with the Collector as some form of assistant (thank you mossbag for this one).

Now, the Dandy's Dream Nail dialogue says "Too long spent together... we become as one...". This, paired with the black streaks around the Dandy's eyes as well as the Void particles seen around the corpse, leads most people to assume that the Collector being made of Void somehow started to physically affect the Dandy, leading to its death. But what if it weren't simply one-way? What if, somehow, the Collector started to mirror the Dandy- if the Dandy was enthusiastic enough about its work, then the Collector may have become obsessed as well due to this.

We also know that the Pale King was attempting to snuff out almost everything he could about the Radiance. The Moth Tribe were apparently born from the Radiance, either metaphorically or literally. While the Moth Tribe did reject the Radiance and follow the Pale King, some moths still chose to remember their old god, until, according to the seer, "all of Hallownest began to dream of that forgotten light". Somehow, this hushed worship of the Radiance could have led to the infection taking hold in the world.

From what I could find, it was not entirely clear if any of the Void experiments began before or after the beginning of the Infection. The Collector could have been created any time in between the creation of Hallownest to its fall- it could be an early, perhaps unfinished form of a Kingsmould- it could be a typical Kingsmould that was altered in some way- it could be a late, more adavnced form of Kingsmould with traits unlike the other more typical Kingsmoulds (for example, it has a voice, where seemingly no other Void being does whatsoever).

Another thing to note- it's not made clear what kind of power exactly the Elegy charm draws from. Because of the Grubsong charm's connection to Soul, one might assume it is also Soul energy, however the slash doesn't draw from the Knight's Soul meter and any charms that directly affect spells or Soul use (other than Grubsong) don't have any sort of affect on the Elegy charm when equipped together.

So, my theory:

The Grubs are actually caterpillars, created by the Radiance in her return to Hallownest. The Pale King, or someone underneath him, noticed the appearance of these bugs and decided to study them- that, or they already knew of the bugs' connection to the moths and thus decided to trap them. The Dandy was the one in charge of this, the head researcher who collected and researched them. The Collector was a Kingsmould gifted to the Dandy by Lurien (or even the Pale King himself) to help with research- and perhaps, if they knew about the Radiance connection, also as a form of extra security (The vessels were Void beings created to contain the Radiance. The Collector is a Void being who obsessively contains Grubs. There's a reflection there). The Collector may have even specifically been granted a voice in order to be able to communicate with the Dandy.

Over time, the Dandy and the Collector being around each other so much caused them to start to become one. Not just in the Dandy becoming somehow infected with Void, but also in the Collector's obsession with the Grubs. This ultimately led to the Dandy locking the Collector in the Tower of Love and attempting to run away with the key before succumbing to the Void in the Queen's Gardens.

Being an experiment specifically created by the Pale King and his court, the Collector likely had some form of "programming" by the court to complete its intended tasks. Unlike the Kingsmoulds' simple programming to Defend the Pale King, instead the Collector's would have been to collect or trap bugs. It could have even been the case that the Collector was the Dandy's field agent- going to collect the Grubs itself so as to not put the Dandy in danger. We can even see this in its attacks- it doesn't necessarily slash at you, but instead makes a grabbing motion. Perhaps the Collector was programmed to Contain and Protect, with protect applying both to the Dandy and the collected specimens (a dead grub is no use for research, now is it?). However, now there seems to be some sort of bug in the programming (pun not intended) where the Collector doesn't seem to distinguish between what it should or shouldn't collect- we see bottles of Vengeflies and Aspids and Baldurs, and even the player's Shade, but these are only ever found within the Tower of Love where the Collector is locked away. It's likely it was the Dandy's orders that told the Collector exactly what to collect, and without those it simply overdoes its programmed task.

Unfortunately, the Knight eventually comes along and destroys the entire operation before we can find out the real truths regarding the Grubs. Hopefully the Grubberflies aren't actually tiny Radiances.