A Shell Block is an object which appears in Mario & Luigi: Bowser's Inside Story and its remake Mario & Luigi: Bowser's Inside Story + Bowser Jr.'s Journey. Jumping at one allows Mario to wear a Blue Shell up until he jumps out of it.

In the games[]

In the clouds high above Toad Town is a giant Shell Block that, upon being struck, releases and spreads several regular Shell Blocks all over the overworld (similar to when activating a ! Switch at the end of a Switch Palace in Super Mario World).

When this occurs, Mario and Luigi are confronted by the Blue Paratroopas. The brothers come up with a purpose for the Shell Block in that while Mario is in a Blue Shell, Luigi can use his hammer to whack Mario forward in his Blue Shell, allowing to hit certain otherwise unreachable objects, followed by Mario spinning back in the Blue Shell like a boomerang.

Characters	Protagonists	Bowser • Luigi • Mario • Starlow
	Antagonists	Dark Star • Fawful • Midbus
	Other Characters	Blue Paratroopas • Bowser Memory Neuron • Bowser Memory P • Broggy • Broque Madame • Broque Monsieur • Chakron • Corporal Paraplonk • Doctor Toadley • Doctor Toadley's intern • Fawful • Giant Sockop • Jerry • Kamek • Kuribo • Kuzzle • Monty Bros. • PR Toad • Princess Lipid • Princess Peach • Private Goomp • Sergeant Guy • Toadbert • Toadsworth • Yikk
	Species	Bee • Blitty • Bob-omb • Brock • Emoglobin • Evoglobin • Goomba • Magikoopa • Nutsoglobin • Shy Guy • Totemglobin • Toad • Virus
Locations	Mushroom Kingdom	Badge Shop • Blubble Lake • Bowser Path • Bowser's Castle • Broggy's Shop • Broque Monsieur's Shop • Bumpsy Plains • Cavi Cape • Conference Hall • Dimble Wood • Fawful Theater • Gear Shop • Peach's Castle • Peach's Castle Garden • Plack Beach • Project K • Star Shop • Tea Kiosk • Toad Town • Toad Town Caves • Toad Town Mall • Toadles Boutique • Toadley Clinic • Tower of Yikk • Treasure Chamber • Tunnel
	Bowser's body	Airway • Arm Center • Challenge Node • Chest Station • Cholesteroad • Energy Hold • Flab Zone • Flame Pipe • Funny Bone • Gut Check • Joint Tower • Leg Outpost • Lumbar Nook • Memory Banks • Nerve Cluster • Nose Deck • Pipe Yard • Pump Works • Rump Command • The Gauntlet • Toad Square • Trash Pit
Enemies	Mushroom Kingdom	Alarm Bob-omb • Beehoss • Borp • Broggy • Broque Monsieur • Chain Chawful • Choomba • Chuboomba • Coalbit • Crawful • Dark Fawful Bomb • Dark Fawful Guy • Dark Mechawful • Dark Mechawful.5 • Dark Trashure • Drillbit Crab • Fawflant • Fawflopper • Fawfulcopter • Fawful Guy • Flifit • Glam Lakitu • Jailgoon • Lakitu King • Magifoofa • Mawful Mole • Mechawful • Metal Mawful Mole • Naplock • Nooz • Pendril • Scutlet • Sneed • Sniffle Thwomp • Sockop • Toothy • Treevil • Trashure
	Bowser's body	Airnapse • Air Cannon • Air Cheep • Bone Thwomp • Bubble Blooper • Calorite • Digital Boo • Dried Blooper • Elite Goombule • Goombule • Napse • Pep • Piranha Plorp • Protobatter • Pwallop • Spike Blop • Stonk • Tenderling
Bosses	Main Bosses	Alpha Kretin • Beta Kretin • Biffidus • Blizzard Midbus • Bowser • Bowser Memory ML • Chakron • Dark Bowser • Dark Fawful • Dark Satellmite • Dark Star • Dark Star Core • Durmite • Junker • Junker Can • Leaf Guy • Midbus • Scutlet • Sea Pipe Statue • Shroob • Snawful • Vacuum Helmet • Wiggler • Wisdurm
	Giant Bosses	Bowser's Castle • Fawful Express • Fawful Mountain • Super Peach's Castle • Tower of Yikk
	X Bosses	Alpha and Beta Kretin X • Biffidus X • Bowser X • Bowser Memory MLX • Dark Satellmite X • Dark Star X • Durmite X • Junker X • Junker Can X • Wisdurm X
Techniques	Mario and Luigi	Falling Star • Fire Flower • Green Shell • Jump Helmet • Magic Window • Mighty Meteor • Snack Basket • Spin Pipe • Super Bouncer • Yoo Who Cannon
	Bowser	Bob-omb Blitz • Broggy Bonker • Goomba Storm • Koopa Corps • Magikoopa Mob • Shy Guy Squad
Items	Consumables	1-Up Deluxe • 1-Up Mushroom • Cheese** • Fiery Drumstick • Heart Bean • Hot Drumstick • Max Mushroom • Max Nut • Max Syrup Jar • Mushroom • Nut • Power Bean • Refreshing Herb • Retry Clock • Special Bean • Star Candy • Super Cheese** • Super Mushroom • Super Nut • Supersyrup Jar* • Syrup Jar* • TNT Drumstick • Ultra Cheese** • Ultra Mushroom • Ultra Nut • Ultrasyrup Jar*
	Key Items	Banzai Bill • Birdley • Blitty • Blue Key • Green Key • Hammers • Miracle Cure • Mushroom Ball • Puzzle Sack • Red Key • Skeletone Formula • Star Cure • Star Panel • Stingler • Vacuum Block • Vacuum Shroom
	Blocks	99 Block • Attack Piece Block • Command Block • Hidden Block • L Block • M Block • Rally Block • Save Block • Shell Block • Shop Block
	Other	5 Gold Coin • 10 Gold Coin • 50 Gold Coin • Blorbs • Boo-ray Machine • Cake • Chakroad • Chombone • Donut • Giga-carrot • Launch Fit • Liftoglobin • Meat • Mushroom Tea • Negative Ions • Nubbin • Scratch Card • Seesaw Fit • Squid Fit • Vegetable • Whirlwind
Miscellenous	Stats	Defense • Experience Point • Heart Point • Power • Rank • Special Point • Speed • 'Stache/Horn
	Status	Balloon Mario • Burn • DEF-Down • DEF-Up • Dizzy • Fire Mario • Fury • Level up • No Skills • Poison • POW-Down • POW-Up • Pump Mario • SPD-Down • SPD-Up • Shell Mario • Sick
	Moves	Body Slam • Fire Breath • Flee • Jump • Shell Defense • Sliding Punch • Spike Ball • Trip
	Other	Bros. Badge • Clothing • Gallery • Glitches • Mario & Luigi RPG: Sound Selection • Pre-release and unused content • Quotes • Shops • Staff • Star Menu
*-Exclusive in Mario & Luigi: Bowser's Inside Story • *-Exclusive in Mario & Luigi: Bowser's Inside Story + Bowser Jr.'s Journey