Bonus Area: Phantom Dish
In FUNGAL FREEWAY (while in TRACK ATTACK/EXPLORATION) you can go up to the stone wall. There will be to little ramps leading to the wall. Both are on either side of a door. Go up both ramps and when you hit the wall stop, this will push in two large bricks. Go to the door in the middle of the two ramps and run into it, this will make it open and you'll be in the bonus area.