Web Woods
It is one of the objects on the end target. It appears for much
less time than any of the other items, you will have to time your
landing very carefully.
After [N], head right past a backwards-pointing arrow of bananas.
You will reach a Klump who fires a slow cannonball. Follow the
cannonball back to the left, where it will open a door when it
crashes into a wall.
After first bonus area, head to the right. You will pass another
backwards-pointing banana arrow. Follow a fast cannonball back
to the left until it hits a wall and opens a door.