Captain Goomba Trial (Gold)
From the Super Mario Wiki
Captain Goomba Trial (Gold) is the secret bonus level of Chucklehuck Woods in the Minion Quest: The Search for Bowser mode in Mario & Luigi: Superstar Saga + Bowser's Minions. In order to obtain this level, the player has to use certain amiibo to unlock it.
This is the fifth of seven bonus levels that involves a captain battling enemies by themselves. Captain Goomba (Gold) is the selected captain to enter this level.
The first battle starts off with seven Tanoombas and a Rex captain. The next one has seven Beanies and a Clumph captain. The third and final battle ends with a single Gold Beanie without any enemy troops beside it.