The Black Hood (くろフード) effect dresses Sabitsuki in a hooded jumper. The effect is found in the Alleyway Hospital by interacting with a person wearing a similar hoodie laying on one of the beds in the room directly right of the room with the doctor and nurse in it.
Once you're in Pipes and Phone Polls, go southeast till you see a small house. This will take you to the Apartments. Go all the way to the end (ignoring the elevator, and the three doors you pass), then go up the stairs. Continue upwards, then interact with moving box. (Be careful! There are enemies here!) Go to the farthest right, avoiding the enemies, and interact with another floating box. After going down the stairs, and all the way to the right, enter the elevator. Coming out of it, go straight (ignoring another elevator) till you end up in a lobby looking place. Continue to go straight and you'll end up outside which is when you go either right or left (you'll see it either way). There should be a white building. Enter, and go through the door.
The door to the right of the room the doctor and nurse are in should have it!
- Pressing the action button causes Sabitsuki to lower her hood and pressing again will raise it back up.