Mega Mole

Mega Moles are a giant species of Monty Moles that are impervious to many attacks. They wear sunglasses and 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.

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

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 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.