Fawful Express

The Fawful Express is a giant train with a Fawful face in the game Mario & Luigi: Bowser's Inside Story and its enhanced remake, Mario & Luigi: Bowser's Inside Story + Bowser Jr.'s Journey. In the game, Bowser meets up with the Monty Bros. he encountered in the Tunnel who drive the Fawful Express, telling Bowser that they had switched sides and were working for Fawful the entire time. They then drive the train into Bowser, forcing Mario and Luigi to make him giant. After becoming giant, Bowser faces off against the Fawful Express.

The train turns around, and attempts to reach the rickety bridge in 100 "kilomoles". if Bowser does not defeat the train by the time it reaches the bridge, he will fall into the valley, resulting in a Game Over. The train is too small to be able to punch, so the only way to defeat the train is with Bowser's fire breath. The train makes a certain amount of stops during the chase, during which Bowser has two whole turns to act, and the train having one attack. After Bowser's second turn, it will move to the next station.

The first two stations, the train will unleash small hordes of Choombas, which will charge into Bowser. He must use the stylus to tap on one of the three dots that appear on the screen to squash the Choombas. Occasionally, a Mushroom will appear. After the two stations, the train will reach a small spiky mountain, where it will fire a missile over and at Bowser. Similar to the Tower of Yikk, Bowser must repeatedly tap the mountain to punch it until it crumbles, evading the missile.

The Fawful Express then hides inside a living mountain, called Fawful Mountain, which Bowser must defeat in order to move on with the main battle. The Monty Moles can repair the express while in the mountain, but if Bowser burns the mountain with fire breath, the train inside will lose some health. After the mountain is destroyed, the train flees to another spiky mountain, which Bowser must also destroy.

The final two stations feature an attack where a group of Monty Moles with jetpacks carry bombs. Bowser must time his punch so that he hits the lead mole while the other moles are all aligned, causing all of them to drop their bombs and heavily damage the train. The final station is Grand Central, and Bowser has two more turns to attack before time is up. If he wins, the train explodes, and a chunk of debris defeats the Monty Bros. as well.

In Mario & Luigi: Bowser's Inside Story + Bowser Jr.'s Journey, after defeating the Fawful Express, the Monty Bros. will get out of the train before Bowser tosses it on the bridge, causing it to fall apart and the train to fall into the abyss.

Trivia

 * The Fawful Express battle is very similar to the Zeekeeper battle in Mario & Luigi: Dream Team, as both battles have the player chase after the boss before stopping for a chance to attack.
 * The Fawful Express is the only Super Bowser boss battle to not have the opening directly show Bowser becoming larger (it instead shows the inside of the conductor's cabin with the Monty Bros. gloating about their success, and then reveals Bowser became large offscreen).
 * Likewise, it is also the only Super Bowser boss fight where the circumstances for Bowser assuming the giant form did not involve him being stepped on or crushed from above (he was instead smashed into a boulder).