Piper is a pipe-inhabiting creature that resembles a Bullet Bill.
History
While the Beanbean Castle Town is peaceful, Mario and Luigi went into the Pipe House, they were about to go through the Red Pipe until Piper popped out looking pleased to see the Bros.. He asks them about what pipe do they want to ask about. When asking about Green Pipes, he explained to jump in one to another place to "elsewhere land". When asking about Yellow Pipes, it explained that they are travelled below the "seafloor and the surface or between above and belowground". If the Bros. allowed him to explain more about pipes, he greets them a goodbye. He told them to "study a little on their own".
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.