The Butterfly Forest (蝶, Chō, Butterfly) is a dark place accessible from the Xylophone Path in Chaos World. As the name suggests, there are lots of butterflies floating around their corresponding butterfly drawing on the ground.
The area has 7 different colored butterflies (some of them might not appear at first), each teleporting to a different area. The same white NPC from Fantasy Library is also wandering around.
The red butterfly takes you to the Red Lily Lake. You will not be able to return to the Butterfly Forest from here..
The cyan one takes you to Blue Orb World filled with lots of blue bubbles.
The green one takes you to a secluded cliff-like area with a waterfall in the background. Approaching the edge will pan up the screen, showing more of the waterfall. There is a chance that the background will be a starry sky instead, interacting with it will teleport you to Candy World. There is a black rabbit-like creature in here which reacts to various effects:
•Fairy will make it turn semi-transparent and run away from you;
•Howling with the Wolf effect equipped will make it walk towards/around you; Eyeball Bomb, Twintails, Maiko, Wings, Penguin, and some more effects do the same;
•Ringing the Telephone or using the Spring effect will make it jump;
•Turning completely invisible with the Invisible effect will cause it to turn into a blue orb, similar to ones in Cloud Floor;
•Equipping the Cast turns the creature white-green and makes it walk towards Urotsuki, causing the effect to be unequipped;
•Child effect turns it white-pink and makes it walk towards you;
•Marginal also makes it run towards you (though MUCH faster);
•Bunny ears make it hop around cutely.
The yellow one takes you to a small lake with some fireflies. It’s only visible while the Bug effect is equipped. If the piano player in the book is killed, there will most likely be no more fireflies in this area and the music will change. It also may snow.
The blue one takes you to Constellation World. It only appears after you visit that world at least once, and you cannot return to Butterfly Forest after coming here.
The pink one takes you to the xylophone path area in Chaos World. It only appears if you’ve visited Chaos World at least once.
The white butterfly can randomly teleport you to 3 different rooms:
•In the grayscale/black and white room, interacting with the north wall will cause Urotsuki to say one of her “don’t/can’t/no” clips.
•In the blue room, interacting with the same wall will teleport you on top of a picture book. Entering the hole in the book will take you to a small room with a white-haired piano player and a sheep. Interacting normally with the player will make them play a different tune, while killing them will turn the room darker and the piano tune will change. Going back out to the book will change it to a red tint and you will be unable to return back to the butterfly. Going back inside the room, there will be nothing but a hole in the ground that takes you to the piano in Snowy Pipe Organ.
•In the yellow-red room, interacting again with that same wall takes you to the sepia version of the Cloud Tops.