Silkeater

Knock down the silk bundle at the top of the tower to release the Silkeater.

Hanging from the ceiling in the hidden cave beyond the breakable wall. Knock it down to grab it.

Attack the hanging cocoon in the bottom-right of the room to obtain the item.

Strike the largest cocoon here to release the Silkeater. It drops on the platform directly below where it was hanging.

You’ll need to navigate through the hidden areas to find this. At the end of the last hidden area, head to the east to find a cocoon you can attack, containing the Silkeater.

Found behind the breakable wall. Wall-jump up to knock it down.

After the first meeting with Styx, they tell you to come back later. Do exactly that, and you will find a Silkeater.

Break the ground in the Ventrica station and follow the path to find this.

There is a cocoon dangling on the right side of this room. Knock it down.

Hanging in a room on the right-hand side of the Exhaust Organ interior.

Credit to Neillionaire for finding this one.