Junker

Junker, or the "Super Ultra Great Mega Trashy Monster Junker Bot" as Midbus calls it, is a trash can-like robot boss fought near the end of Mario & Luigi: Bowser's Inside Story. It is helped by several smaller cronies known as Junker Cans, which it can call on during battle.

Junker is encountered while infiltrating Peach's Castle Garden near the end of the game. Upon entering the back area of the garden where the secret entrance was supposed to be, Starlow comments that there is nothing but trash. 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 in a rage 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
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 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.

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 or on top of Junker as it attempts the ramming portion of the attack to avoid massive damage. A third attack consists of emptying the garbage from one of the Junker Cans that follow it. Often, this garbage consists of random enemies that go after the Mario Bros, which include:
 * Cheep Cheeps, who jump over the Mario Bros. and hurt them if they jump.
 * Bob-ombs, who light their fuses before charging.
 * Scutlets, which immediately charge after coming out.
 * It also contains useless objects like a pair of briefs and a wad of paper.

Once several enemies have attacked, the Junker Can is discarded. If Mario or Luigi defeats a Junker Can, a Chain Chomp or a Fish Bone may appear. The Fishbone circles Mario or Luigi, and if not hammered, rams into them. The Chain Chomp charges at one of the brothers, who must counter it with the hammer. The Chain Chomp can also inflict poison.

The Junker can also choose to hinder the Mario Bros. and incapacitate Luigi by putting him into a Junker Can. Since this attack cannot be avoided, Mario is forced to defeat the Junker Can to rescue his brother. Occasionally, Luigi hits the rim and escapes on his own. On other occasions, Luigi will wave to Mario while in one of the Junker Cans, signifying which one he is trapped in. After doing this, the can's lid slams on Luigi's hand. If Mario is defeated while Luigi is still trapped in the Junker Can, Luigi will be instantly defeated as well, resulting in a Game Over if the player does not have any Retry Clocks (or chooses not to use one). In the remake, the player can now mash so Luigi can escape Junker's suction that puts him in a Junker Can.

After the battle, Junker begins to malfunction again, rampaging around and freeing Bowser from the safe he was trapped in earlier. It then destroys itself by running through a pile of trash, allowing the Mario Bros. to access a pipe connecting Peach's Castle to Pipe Yard.

A stronger version of Junker called Junker X can be found in The Gauntlet.

Trivia

 * The attack in which it throws Thwomps at the brothers is a reference to the Super Famicom game Mario & Wario.