This can only be done in the "Old House". When you meet Marguerite, she will block a door with spiders. You can use your knife to cut them off, use ranged attacks to avoid damage. If you do not do it here, there will be some lockers, blocked by spiders, during the Marguerite boss fight that you can do this on.
Here is a video guide with English commentary!
Here is a playlist of guides for this game!
https://www.youtube.com/playlist?list=PL-HeW6XkKdUKUtj7CV_kW...