From the Super Mario Wiki
The Guffawha Ruins are the dusty, deserted structures that Luigi (under hypnosis) visits during Mario & Luigi: Superstar Saga to find a cure for his brother's Bean Fever. In this dungeon, Luigi has to take out a few enemies on his own such as Chuck Guys, Oucher Glasses, and Limbo Bros. He will then have to solve several puzzles. At the end of the level, there is a big rock shaped like a head, the Guffawha Monster, who will ask Luigi to relieve his stress by dodging energy balls he spits out for 30 seconds. Many people in Little Fungitown thought this rock head was a flesh-stripping, bone-crushing, bloodsucking monster, although he doesn't harm Luigi or challenge him to a battle. However, once Luigi finds the Crabbie Grass and exits the ruins, there is no way to gain access into this place again. Guffawha Ruins lies between Teehee Valley and Hoohoo Mountain.
Names in other languages