The SPIDER AREA is a long blue walkway filled with trees and spider webs. The area's overall structure resembles that of VAST FOREST but the colors are all inverted and out of place. There are several spiders roaming all over the ground. OMORI has to first cut BASIL free from a spider web he's trapped in.
From there, OMORI and BASIL can navigate their way through the location. Their movement will soon become slower as BASIL slowly becomes covered by multiple spiders. Eventually, after BASIL gets devoured by the spiders, OMORI can move around freely and retrieve the key by following some red footprints.
There is only one NPC that can be interacted with, that being the giant mother spider found on the top left corner of the area. Interacting with the giant spider will reveal it as dead and one of her offspring has passed away out of sadness. A few floating centipede creatures can be seen wandering around the walkway.
When OMORI enters the room, BASIL is trapped in a spider web, but is freed by OMORI. He follows OMORI as they search for an exit. As they walk however, BASIL decides to mention he wants to talk about something, presumably the truth, which leads to him getting covered in spiders.
The number of spiders continue to increase as they continue to walk, though BASIL denies any risk. They keep increasing until they completely cover BASIL, devouring him entirely. Afterwards, red footprints will lead OMORI to the key. After collecting the key, several RED HANDS will spawn and interacting with them will take OMORI back to the center hub of BLACK SPACE.
Oh, thank goodness you're here, OMORI. I thought I was gonna be stuck here forever.
Umm... OMORI? Aren't you forgetting someone?
Phew... That feels so much better.
I can't believe you came here to save me. I missed you so much!
Now that you're here, I can finally go home. Lead the way, OMORI!
You know... I think spiders are really misunderstood... They might look kind of scary, but they never attack humans unless they feel threatened.
Not to mention they're also one of my biggest helpers when I'm gardening, since they eat a lot of the pests that can hurt my plants. It's all about the balance of nature!
I remember a while back... You told me that a big spider fell on your shoulder just as you were about to dive into the lake at our secret hangout spot!
I know that the spider must have looked so scary to you, but I promise that you probably looked a lot scarier to the spider! No offense, of course... Haha...
There's so many spiders here all of a sudden... I can feel them crawling all over me. Maybe they're just saying hello?
Hi, spiders! It's me, your friend BASIL!
Ack! They're biting me!
Oh... I'm probably just scaring them.
There there, spiders. It's okay! I'm not here to hurt you!
There's so many of them... I can't get them off!
OMORI... Please... help...
A full view of the Spider Area with no background.
Basil slowly getting eaten alive by the spiders that slowly surround him.
Basil getting completely devoured by the spiders.
The corpse of the Mother Spider.
The centipede creature from the Spider Area.
BASIL's commentary regarding how spiders are actually helpful instead of harmful is later reused during the PYREFLY FOREST picnic sequence on ONE DAY LEFT of the OMORI ROUTE.
The memory BASIL mentions in the SPIDER AREA refers to the time when SUNNY nearly drowned in the past at the HANGOUT SPOT's lake and MARI had to swim down to rescue her brother.
It's also possible that this area is based on SUNNY's irrational fear of spiders.
When BASIL slowly gets consumed by the little spiders, the SOMETHING fear border representing the fear of spiders can be faintly seen covering the screen. The fear border disappears once BASIL is entirely devoured by the spiders.
The SPIDER AREA is one of the ten optional BLACK SPACE areas the player can explore. It is also one of the few areas where BASIL can be found.
The flying centipede creatures in this area are referred as SNAKEHAND in the game's files.
It is possible to softlock the game in this room. After the events with BASIL occur, the player can stab themselves without collecting the key. This renders OMORI unable to access any other doors in BLACK SPACE, as a key is required in order to continue.
↑The RPG MAKER MV project of the game labels this area as SPIDER FOREST.
↑ This Reddit Thread details a person's experience with this bug