When you enter the first boss door, you are warped into a dark tunnel. Behind you appears Tom, wearing a pair of sunglasses. He says he's gonna flatten you like a pancake and starts rolling after you. This isn't so much of a boss fight as a test of endurance. The key is to keep running while avoiding obstacles in your way. Rainbow Dash any Fluttershy can jump and hover over obstacles, so they're a good choice. As you run, Tom will start moving faster and faster. Tripping over obstacles will deal damage and slow you down, If Tom squashes you, it's game over. However, if you run fast enough and keep it up, after three minutes or so, you'll reach the end: a short wall that you can hop over. However, Tom will just hit the wall hard, causing a chain reaction that will result in a cave in that will trap and crush Tom for good. You will then warp back into the labyrinth and journey on to the second boss door.
Actual Music: O'Chunks' Battle Theme from Super Paper Mario
Artwork: i am a brony dot com: http://iambrony.com/gif?page=15&type=Contributed