Yume Utsutsu (ゆめうつつ)/guide

Scooter (スクーター)
Enter the Roadsign World. Go north-west and enter the large sign in the ground. Go up and take the curved road. Go up again and interact with the scooter.

Squid (イカ)
Enter the Eyeball World. Go right and down from the entrance. Enter the large eyeball with a hole in it. Interact with the squid.

Laminated Paper (ハリボテ)
Enter the Mural World. Go south-east and find another Uboa-like mask in a small walled-around section. Go up and slightly left from where you're teleported and interact with the wooden sign.

Sunglasses (サングラス)
Enter the Roadsign World. Go south-west and interact with the green NPC.

Black Hair (くろかみ)
Enter the Mural World. Go south-east and find/interact with a Uboa-like mask on the wall. Head down and interact with the wall with no mask on it near the bottom. Interact with the monochrome NPC.

Knife (ナイフ)
Enter the Concrete Maze. Go: Left once, Down twice, Right once then Down. Enter the building. Go right until you're teleported to another area. Go north as far as you can and interact with the knife.