Junker X is the fifth boss encountered in The Gauntlet in the game Mario & Luigi: Bowser's Inside Story. Players are charged 1800 Coins to fight it and the player must beat it in 15 turns or fewer. Compared to Junker, Junker X has higher HP, power, defense and speed, and its attacks are more difficult to evade. Junker X is blue with pink details and its Junker Can Xs are brown with pink eyes.
In battle, Junker X has a variety of attacks. One attack consists of throwing a bucket over either Mario's or Luigi's head. The brother will then stumble around blindly while Junker X throws Thwomps at him; players must time their jumps to avoid the attack. If Mario or Luigi are hit by the Thwomp, they may get dizzy. This attack is a reference to the Super Famicom game Mario & Wario.
Another attack involves throwing two balls of metal scrap at one of the Mario Bros., then attempting to ram him. The brother in question must jump onto the balls, then jump over Junker X as it attempts the ramming portion of the attack. A third attack consists of emptying the garbage from one of the Junker Cans that follow it. Often, this garbage will consist of random enemies that go after the Mario Bros, which include:
Once several enemies have attacked, the Junker Can will be discarded.
The Junker X may also choose to hinder the Mario Bros. and incapacitate Luigi by putting him into a Junker Can. Since this attack cannot be dodged, Mario will be forced to defeat the Junker Can to rescue his brother. Occasionally, Luigi will hit the rim and escape on his own; on rarer occasions, Luigi will wave to Mario while in one of the Junker Cans. After doing this, the Can's lid will slam on Luigi's hand. If he is not freed and Mario is defeated, the player will need to restart the battle.