Mega Mole

Mega Moles are a giant species of Monty Moles that are impervious to many attacks. They act as bosses over the other Monty Moles.

Super Mario World / Super Mario World: Super Mario Advance 2
In Super Mario World and its remake, Mega Moles are exclusively found underground, appearing in Chocolate Island 4, Valley of Bowser 1 and Valley of Bowser 2. They are invulnerable to Mario and Luigi's jump or Spin Jump moves as well as Fire Mario or Luigi's fireballs, but can be defeated by using Caped Mario or Luigi's spinning attack, a Super Star, a Grab Block, or a Shell. Like other enemies, they are also immune to hazards such as Munchers and spikes. Standing on a Mega Mole's head is not a danger by itself, and will allow Mario or Luigi to ride it. Unlike regular Monty Moles, they do not pop out of holes in the ground. Despite their size, they can be eaten and swallowed by Yoshi. While most enemies merely result in the loss of Yoshi when getting hit by them, a few others, including Mega Moles, both hurt Mario and force Yoshi to run away. In the remake, if Yoshi eats a Mega Mole and spits it out while Luigi is riding him, a unique sprite of it facing the screen (thus resembling Monty Mole's jumping sprite) can be seen as it rolls along the ground.

Super Mario-kun
Mega Moles have made multiple appearances in Super Mario-kun.

A friendly Mega Mole has a major role in one of the chapters from volume 1. Mario, Luigi, and Yoshi land on top of the Mega Mole, which scares it but it soon takes off its sunglasses and introduces itself. After it falls into a pond, Mario is able to use his Frog Suit and a Power Balloon that Luigi tosses to help carry the Mega Mole out of the water. After this, the Mega Mole leads Mario and his friends through a cave until they stumble upon a Skull Raft. They use it cross the lava until a Blargg comes and attacks everyone. The Mega Mole jumps into the Blargg's mouth, clogging it. As the Blargg retreats into the lava, the Mega Mole re-emerges with the Blargg attached to its head.

In a Mario Paint-themed chapter from volume 5, Lemmy Koopa is able to make a crudely drawn version of Mega Mole as well as other Mario enemies using the SNES Mouse. However, the Mega Mole alongside the other enemies are quickly beaten up by Mario and Yoshi.

A Mega Mole driving a kart working for Bowser has a major role in a chapter from volume 6. When Mario and his friends go through an ice area, they come across The Mega Mole accidentally breaking the ice underneath them, which makes Bowser and the Goomba laugh at it. The Mega Mole then gets picked up out of the ice by three Lakitus before driving towards Mario. However, Luigi knocks Yoshi onto the Mega Mole's face. Luigi them attempts to throw a Poison Mushroom at the Mega Mole, but it smacks away Yoshi and the Poison Mushroom, making the Poison Mushroom land in Mario's mouth. Mario then straps Yoshi to his kart with Yoshi breathing fire at the Mega Mole causing them to drive in circles. The Mega Mole then uses its kart to hover over the water, spring into the air, and crush Mario, making him fall below the ice. After the Mega Mole congratulates itself for defeating Mario, Mario bursts out using Lightning to zap and shrink the Mega Mole. Mario and his friends then proceed to bury the Mega Mole in a snow sculpture of itself as Bowser laughs through the situation.

A Mega Mole appears in volume 7, in which it walks up to Mario and tries to be tough at him. However, Mario picks up the Mega Mole (referencing Super Mario Bros. 2) and throws it at Yoshi.

Although normal Mega Moles do not appear in volume 9, a Piranha Plant-Mega Mole fusion known as Pakkun Mogura is seen as the main antagonist of the second chapter.

Nintendo Adventure Books
In the Nintendo Adventure Book Dinosaur Dilemma, if Mario offers apples to Yoshi and some dinosaurs he finds near Lake Trilobite, a Mega Mole will burst out of the dinosaur costume seizing Mario's sleeve. The other dinosaurs (including Yoshi) will turn out to be Mega Moles in disguise, and will surround Mario after removing their costumes, leading to a Game Over. Some more Mega Moles can be encountered the basement of a decrepit mansion, where two furry objects can be seen in the distance blocking the exit sign. If Mario goes deeper in the cellar, he meets three more Mega Moles that sniff him before biting him and chasing Mario, attempting to eat him. If Mario chose the right path, he remembers that Mega Moles have poor eyesight and steps out the way making the Mega Moles go by as he escapes. Choosing the wrong path will lead to a Game Over, when Mario blindly falls into a watery pit inhabited by a Blargg.

Some Mega Moles appear among the crowds at the International Dino-Flying Derby in Flown the Koopa, and eye Mario and his friends hungrily when the show ends. Later in the swamp, if Mario and Luigi don some Mega Mole costumes, six real ones will approach the two with gifts. After "befriending" the Mega Moles by singing old plumbing songs and exchanging cookie recipes, Mario and Luigi have a plan to go in their cave and load up on supplies, before bursting through the castle with the help of the Mega Moles. Once they arrive at the Mega Moles' cave lair, the Mega Moles continue stuffing the plumbers with food, before weighing them down with "gifts". Mario then looks at the books before grabbing a book called Mega Moles In The Mist by Diane Flossy. As the Mario Bros. realize that the Mega Moles brought other people to their lair, trapping them, Mario realizes his fate before finishing the book, leading to a Game Over. Finally, another group of Mega Moles will attack Mario and Luigi, causing a Game Over, if they decide to explore a dark portion of Magikoopa's Fortress with a flashlight, which quickly dies on them since the Mega Moles can see very well in the dark.

In Unjust Desserts, some Mega Moles are shrunk by Magikoopa, and sent into Yoshi's body after Mario, though the hero never encounters any inside the dinosaur, just in the palace garden when he and all the creatures Yoshi and Luigi had eaten are spat up by them.

Super Mario Adventures
In Super Mario Adventures, multiple Mega Moles seen wearing blue tuxedos can be seen attending Bowser's wedding in the penultimate issue.

Mario Family
A Mega Mole appears in Mario Family, as one of the sewing designs.

Mario Strikers Charged
In Mario Strikers Charged, the sprites for Mega Moles seen in Super Mario World can be seen on the pillars in The Sand Tomb.

Trivia

 * In Super Mario 64 source assets, Monty Mole's model is internally labeled "indy" and has its size set to 25% of the base model when implemented in-game, indicating the original intent for them was to be Mega Moles.
 * Mega Moles appeared in a Mario-themed commercial, being much smaller then they are normally. When Yoshi eats one of the Mega Moles, he spits fire, which does not happen in Super Mario World.
 * Mega Moles are confirmed to be eight feet tall in Flown The Koopa, though they are around the same height as Mario in Super Mario World and on the size chart for the 1993 Nintendo Character Manual.