Junker

Junker is a boss fought near the end of Mario & Luigi: Bowser's Inside Story. It is a robotic creature resembling a trash can. It is helped by several smaller monsters known as Junker Cans.

Junker is encountered while infiltrating Peach's Castle Garden near the end of the game. Upon entering a certain area of the garden, Starlow will comment that there is a lot of garbage laying about. After Mario and Luigi progress to the end of this area, Midbus appears, holding some sort of remote control. When it is activated, Junker springs to life from the piles of garbage laying around the area. After Midbus's attempts to control it fail, he smashes the remote and allows it to fight the Mario Bros. on its own. Midbus's attempt to control the Junker may demonstrate why it was in the garbage in the first place, as it began to dance when he commanded it to attack.

Battle Strategy
In battle, Junker 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 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 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:
 * Cheep Cheeps, who will jump over the Mario Bros. and hurt them if they jump;
 * Bob-ombs, who will first light their fuses before charging; and
 * Scutlets, which will immediately charge after coming out.
 * It will also contain useless objects like a pair of briefs and a wad of paper.

Once several enemies have attacked, the Junker Can will be discarded. The Junker 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 get a Game Over, provided he or she has no Retry Clocks.

After the battle, Junker begins to malfunction again, rampaging around and freeing Bowser from captivity in the process. It then destroys itself by running into a locked gate, opening said gate in the process. This allows the Mario Bros. to access a pipe connecting Peach's Castle to Pipe Yard.

Junker X
Junker X is the fifth boss encountered in The Gauntlet. 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.

Trivia

 * "Junker" is the only boss outside Bowser's body to be encountered in The Gauntlet, besides Bowser X.
 * Junker is called "Super Ultra Great Mega Trashy Monster Junker Bot" by Midbus, but this is shortened to just "Junker" in battle.
 * Junker's habit of trapping Luigi in a minion is very similar to Antasma.