From the Super Mario Wiki
Junker Cans are enemies that resemble garbage cans found during the events of Mario & Luigi: Bowser's Inside Story. They assist Junker while battling Mario and Luigi in Princess Peach's Castle.
They will attack by getting close to the bros., trying to slam them, but this attack can be countered by using the Hammers. However, they will stop short if they see the hammer, and then close its lid, preventing them from taking damage; they must be countered as quickly as possible, but not too quickly. Junker may occasionally pick up Luigi and throw him in a Junker Can, and cannot get out until Mario hammers and defeats the Junker Can holding him. If Mario is defeated with Luigi still trapped, the can will drain his health and KO him as well. Junker can grab Junker Can can drop Cheep Cheep, Bob-omb, and Scutlet you can't kill them. After everthing is out of Junker Can Junker will throw Junker Can and K.O it.
If Mario and Luigi do defeat a Junker Can, a Fishbone, Chain Chomp, or Nooz will head for the bros. that attacked it.
Junker Can X
Junker Can X appears within Bowser's Body located in the Challenge Node, along with Junker X. They have the same battle tactics as the original Junker Cans, just much stronger and faster. Junker Can X also differs in color of the original version, being brown with pink eyes unlike the silver/blue color combination with yellow eyes.
Names in other oanguages
||Pun on Disimulo (Stealth) and Lata (tin).