Silksong Alchemist’s Assistant Quest Guide – How to Find Plasmium and Survive the Wormways October 3, 2025

Deep in the delightful, worm-infested hellscape known as the Wormways, you’ll stumble upon a shady character named Alchemist Zylotol. This guy is obsessed with a glowy, gooey substance called Plasmium and, surprise, he wants you to fetch it for him. This kicks off the “Alchemist’s Assistant” quest, and trust me, the reward is worth getting your silk dirty.

Before you go gallivanting off, there are a couple of things you absolutely must do. This isn’t amateur hour, after all.

1. Unlock the Wormways: Obviously. You can’t be an assistant if you can’t get to the lab. You’ll need a Simple Key to get in, which you can either buy from Pebb (if you’ve got the Rosaries) or pry from the cold, dead hands of a boss on Sinner’s Road. Your call.
2. Get Clingy: The Wormways are a vertical nightmare. You’re going to need the Cling Grip ability to scale its treacherous walls. If you don’t have it, go get it from Shellwood first.
3. Equip the Needle Phial: Zylotol will give you this nifty gadget. Don’t just admire it—sit your butt down on the nearby bench and equip it in your trap slot. If you forget this step, you’ll be staring at Plasmium buds like a fool, unable to collect them. Don’t be that person.

Got all that? Awesome. Let’s go find some space goo.

Where to Find the Goods: All Plasmium Locations

Plasmium looks like a bright blue, glowing flower, which is super helpful because the Wormways are darker than my soul. They won’t show up on your map, so you’ll have to use your big-bug senses. Follow my lead, and you’ll be back to Zylotol in no time.

Plasmium Location 1: Just Around the Corner

The first sample is basically a freebie to get you started.

• Leave Zylotol’s lab and drop down one level.
• Hang a left, dodge the gross falling worms and a spike pit (classic).
• You’ll see the unmistakable blue glow in a little alcove nearby.
• Whip out your Needle Phial and hold that button down to slurp up the good stuff. One down, two to go.

Plasmium Location 2: Deeper into the Gunk

Alright, time to venture a little further from home. This one’s hiding in the lower, mossier part of town.

• From where you found the first sample, head down. Like, way down. Keep descending a couple of rooms.
• You’ll enter a darker area. Stick to the right as you go.
• The scenery will get greener and mossier. That’s your cue! Look for the next glowing Plasmium bud tucked away in a corridor on the right. It’s trying to be coy, but its glow gives it away.

Plasmium Location 3: The Super Secret Stash

The last one is for the real explorers. It’s hidden behind a secret wall, because of course it is.

• From the second location, head left and go down past some spikes and a cranky little enemy.
• Go up and then left into the next room, dashing to avoid more of those falling worm-jerks.
• Keep heading left until you smack into a dead end. But is it really a dead end?
• Use your Wall Climb ability to slide down the wall, avoiding the spikes below.
• You’ll land on a platform. See that wall to your left? It looks suspicious. Give it a good whack to break it open.
• Follow the secret path, do a little platforming, slide down one more time, and voilà! The final Plasmium sample is all yours.

The Payoff: What You Get for Your Trouble

Once you’ve collected all three samples, haul yourself back to Zylotol’s lab. He’ll be thrilled (in his own weird, alchemical way) and will reward you with the Plasmium Phial.

This thing is a game-changer. It’s a tool that grants you three temporary health masks when you use it. It’s perfect for when you’re about to face a brutal boss or explore a particularly nasty area. The Phial comes with 20 charges that refill at benches, so you can keep on living dangerously.

Completing the “Alchemist’s Assistant” quest doesn’t just get you a sweet new toy; it makes you tougher, more resilient, and ready to take on whatever other horrors Hollow Knight: Silksong throws at you. Now get out there and show Pharloom who’s boss.

For more gaming content, visit Total Apex Gaming