Captain Koopa Troopa Trial
From the Super Mario Wiki
This is the third of seven bonus levels that involves the captain battling enemies by themselves. Captain Koopa Troopa is the selected captain to enter this level.
There are two battles in this level; the first has two Clumphs in the front lines, as well as a Limbo Bro captain. The next one has two Tanoombas and three Clumphs, as well as another Limbo Bro captain.