The kingdom of Pharloom is full of dangerous detours and quiet requests, and few side tasks in Hollow Knight: Silksong capture that balance as well as the Advanced Alchemy quest. This mission begins deep in the third act, after Hornet has already begun to understand the strange, shifting politics of the Citadel and the tunnels beneath it. Players who venture into the Wormways will find a claustrophobic region filled with scraping claws, spitting creatures, and a secret chamber that tests their preparation. The walkthrough below describes the entire quest from the initial key hunt to the final hidden encounter.

🗝️ Gaining Access to the Wormways

The Wormways are not an area that Hornet can simply stumble into. A Simple Key is required to open the way, and these keys are hidden in several locations across Pharloom and the Citadel. Explorers who have been thorough in the early and middle acts will often have one on hand, but those who do not may need to retrace their steps through previously cleared districts. Before setting out, it is wise to stock up on healing items and to check the current tool loadout, because the enemies inside are aggressive and the secret boss at the end can punish careless movement.

Once inside the Wormways, the atmosphere shifts immediately. The tunnels twist downward, damp stone gives way to organic-looking walls, and the sounds of hidden creatures echo from above and below. This is the setting for one of the more unusual alchemy-related tasks in the game.

🔬 Revisiting Alchemist Zylotol

Players who completed the Alchemist’s Assistance quest in Act 1 or Act 2 will already be familiar with Alchemist Zylotol. When Hornet returns to him during the Advanced Alchemy quest, however, he is almost unrecognizable. The alchemist has been experimenting on himself in a desperate attempt to become a direct source of Plasmium. His altered appearance is unsettling, but his request is straightforward enough. He offers to refill Hornet’s Plasmium reserve, which is useful for those who rely on Rosaries, and then hands over a special tool.

The Needle Phial is a small extraction device used to draw Plasmified Blood from living creatures. It functions less like a container and more like a charged weapon. Hornet must equip it, approach an enemy, and hold the input until a distinct click is heard. Releasing at that moment rips the Plasmified Blood out of the target and kills it in the process.

🩸 Collecting Plasmified Blood in the Depths

Descending from Zylotol’s location leads to two main types of hostile creatures. One is a burrowing enemy that can spit projectiles and charge across the floor with little warning. The other clings to the ceiling and attacks from a distance, making it difficult to reach with ordinary melee strikes. Both are dangerous, but both are also viable targets for the Needle Phial.

The extraction process requires patience. A player cannot simply tap the button and expect success. Instead, the phial must be charged while near an enemy, and the charge can be interrupted if Hornet takes a hit. This raises a practical question: how should a player handle two enemy types at once? The safer approach is to eliminate the ceiling spitter first, since its ranged attacks can interrupt the charging sequence. The burrowing enemy can then be baited into a charge, dodged, and struck during its recovery.

This extraction must be completed ten times. It is not necessary to collect all ten samples in one trip, although the enemies do respawn if Hornet leaves and returns. Players who struggle with the timing may want to clear a small room, extract from one creature, and retreat to a safer ledge before repeating the process. The click sound is the most important cue; once it is heard, release the input immediately.

💠 The Reward: Plasmium Gland

After ten successful extractions, Hornet can return to Alchemist Zylotol and hand over the gathered Plasmified Blood. His wish is fulfilled, and in return he grants the Plasmium Gland. This permanent reward is far more useful than a simple trinket. It allows the crafting of new Plasmium Phials without the need to spend existing reserves.

For any player who combines Rosaries with Plasmium tools, the Plasmium Gland represents a significant shift in resource management. Instead of scrounging for refills or rationing every last drop, Hornet can craft Plasmium Phials more freely, opening up more aggressive or more experimental playstyles in the back half of Silksong.

⚔️ The Hidden Encounter Beneath the Wormways

Before leaving the Wormways, curious explorers should head to the bottom left of the area. There, a breakable wall sits on the left side of a lower chamber. Breaking through reveals a hidden passage that leads to a secret boss encounter. The fight itself is not mandatory, and its difficulty depends heavily on which tools the player has equipped at that point. Those with upgraded needles, strong Plasmium phials, and a full supply of healing items will likely find it manageable, while underprepared players may be caught off guard by the enclosed arena.

Is the hidden boss worth the extra risk? For completionists and players who enjoy uncovering Silksong’s many buried secrets, the answer is almost certainly yes. The Wormways hold more than Plasmified Blood; they hold a quiet piece of Pharloom’s stranger history, tucked behind cracked stone and guarded by something that does not want to be found.

The Advanced Alchemy quest is a compact but memorable part of Hollow Knight: Silksong’s third act. It combines a disturbing NPC arc, a timing-based extraction mechanic, and an optional hidden fight into a single underground excursion. With a Simple Key, a steady hand, and a willingness to listen for the click of the Needle Phial, Hornet can complete the task and leave the Wormways with a rare reward and a new understanding of the alchemist’s obsession.

Completing the Advanced Alchemy quest is a satisfying milestone, but it is just one of many secrets baked into Silksong’s sprawling map. Between the lore, the boss fights, and the steady gear progression, Hornet’s journey offers far more content than a single trip through the Wormways can reveal, which is part of why the game holds up so well across dozens of hours of exploration.

Players who are still on the fence about adding Hollow Knight: Silksong to their collection may want to check the game deals today at DealNest to see if the price has dropped to a more tempting range. Finding the game at a discount makes the investment in Pharloom’s many mysteries easier to justify, and the hours spent hunting down Plasmified Blood will feel all the sweeter when the price tag is a little lighter.