Lava Dome

From the Super Mario Wiki

Lava Dome is a place in Mario vs. Donkey Kong 2: March of the Minis. The area is very dark, and in the backround there's a volcano. This area also contains has a lot of lava, and Jetpack Guys can be seen here too. It's located the fifth world. The music in this level is an remix of the Bowser's Castle theme from the orginal Super Mario Bros.. These levels have Podoboos and Fire Bars.