The Guffawha Monster is first seen right before Luigi obtains the Crabbie Grass. The Guffawha Monster then appears and tells Luigi he is angry the people are making rumors about it being a blood-thirsty monster. The Guffawha Monster then asks Luigi to help it relieve his stress by jumping over its flames for thirty seconds. Luigi does so and the Guffawha Monster is pleased and opens the way to the Crabbie Grass.
Trivia
The theme song that plays during the Guffawha Monster's mini-game is the boss theme song for Mario & Luigi: Superstar Saga. Though, technically, the monster doesn't count as a boss.
The way the Monster leaves after the minigame is done is different in both versions of the game. In the original, he fades after opening the way to the Crabbie Grass whereas in the remake, he poofs away after opening the gate.
Go, Goomba, Go! • This Beans War • For the Love of Hammers • Winged Traitors • The Hoohoo Melee Brigade • The Great Hammer Barrage • Don't Fear Flying Foes • Goombas vs. Goombas • The Amnesiac Koopa King • Goombas Galore
Turnip Tantrum • Minions vs. Minions • Hunger Pains • A War of Shy Guys and Flybys • Battle Tail • Beanbean Crossfire • The Rival Trio • Larry's Fortress • Captain Shy Guy Trial • Professor E. Gadd's Research • Oh, Hi, Shy Guy! • Shell Brigade, Move Out!
The Sweet Smell of Soda • Deep Trouble • Forest Masquerade • Reclaim the Red Goblet! • Gold Beanie Appears • Invisible Leaderership • Ice Guys Finish Last • The Tough-As-Nails Squad • Forest Fight • Popple's Partner • Captain Goomba Trial (Gold) • Shy Guy Goes Overboard • King of the Boos
A Dry Bone to Pick • The Trouble with Toads • Flying Beans in the Desert • Find the Invincibility Mushroom! • Gold Beanie Spotted! • Silly Ol' Goomp • Ice Bros. Feel the Heat • The Lonely Koopa Troopa • Toad Rescue • Captain Koopa Troopa Trial • Popple's Partner, Part 2 • A Goomba Tail • A Muster of Masks
Goombas Unite • Gather the Cruiser Parts! • Power Play • Spear Party on Ice • Monochrome Explosion • Gold Beanie Fights Back! • Return of the Koopa Cruiser • The Trio's Last Stand • Captain Boo Trial (Gold) • Boo Party! • Shy Guy Barrage
Fireball and Boomerang Crossfire • Chain Chomp and Spike Stomp • A Tale of Tails • Double Trouble Koopaling Caper • Pokey Panic • Rumble in the Castle! • Gold Beanie's Final Stand • Goomba's Worth • Showdown Time!! • Believe in Bowser • Captain Boo Trial • The Mightiest Minions • The Beastly Bean Battalion
• ⋆-Enemy, boss, or stat exclusive to the main game. • ⋆⋆-Enemy, boss, or stat exclusive to Minion Quest: The Search for Bowser. • ⋆⋆⋆-Enemy variants differ in Mario & Luigi: Superstar Saga + Bowser's Minions.