Fireball and Boomerang Crossfire
From the Super Mario Wiki
This level consists of three battles; the first one consists of some Fly Guys in the front and several Fire Bros. in the back, as well as a Fire Bro captain. The next one is much the same as the first, except that Boomerang Bros replace all of the Fire Bros. The last one also has four Fly Guys in the front, except it has two Boomerang Bros and one Fire Bro in the middle, and a Big Boo captain.