The Forest World is one of the 12 original worlds accessible directly from The Nexus. It is located at the 11:30 position, and is door 12 on the Nexus Map.
Description
A Forest area with a part of the Aztec Rave Monkey as its Parallax Background. There are several purple or pink slug-like blobs placed randomly in the forest that do nothing to you when touched. However, if they are interacted with, they'll make a sound and a wobbly transparent image of them will begin to hover above Madotsuki's head.
You can get to the Face Carpet Plaza by touching the gate located to the upper right of the entrance.
The Frog Effect is available in this world. Look for a frog hopping around between trees in the upper left area.
Connections
Face Carpet Plaza - Reached by going through two blue-ish pillars.