From the Super Mario Wiki
Bumpsy Plains is a small grassy area from Mario & Luigi: Bowser's Inside Story. It is located west of Dimble Wood, north of Cavi Cape, east of Blubble Lake, and south-west of Bowser Path. It is filled with many Flifits, as well as Sneeds that only Mario and Luigi can fight. A Chakroad is also located around here and there are only four Beans hidden throughout the area. The music played here is the same as the music played at Blubble Lake. A hidden Squid Fit is found here. Somewhere, there is a trapdoor activated by body-slamming. It is hidden in the ground.
 Names in Other Languages