Heaps of Hammers
From the Super Mario Wiki
Heaps of Hammers is a level in Bowser's Castle (East) in the Bowser Jr.'s Journey mode of Mario & Luigi: Bowser's Inside Story + Bowser Jr.'s Journey.
This level is where Hammer Bros first appear. This level contains two battles. The first battle features five Goombas, two Hammer Bros, a Goomba first officer, and a Goomba captain. The second battle has four Goombas, three Hammer Bros, a Goomba first officer, and a Goomba captain.