Pile Driver Micro-Goomba
From the Super Mario Wiki
Pile Driver Micro-Goombas are a special variety of Micro-Goomba that hide in Brick Blocks. The only games they have appeared in are Super Mario Bros. 3 and its remakes. These Micro-Goombas are quite strong for their size, as they are able to jump extremely high and long while lifting the much larger Brick Block. The Pile Driver Micro-Goomba is also resistant to fire attacks, as it is protected by its Brick Block (which cannot normally be destroyed by fire as well). While their Mugger Micro-Goomba cousins can only slow down the Mario brothers, Pile Driver Micro-Goombas can directly damage them.
Pile Driver Micro-Goombas first appeared in World 2-1, the first area of Desert Land, and were a staple enemy in the various desert and sky levels throughout the rest of the game. In these levels, Pile Driver Micro-Goombas were typically hidden among normal Brick Blocks, although some stayed out in the open. When a Mario Brother approached the hidden Micro-Goomba, the creature would jump high in the air and attempt to crush the hero. However, a Pile Driver Micro-Goomba would lift its Brick Block a couple of times before jumping, providing the plumber with enough time to dodge the upcoming attack. The Mario Bros. could destroy these enemies by stomping the block-shielded Goomba, hitting the creature with the Raccoon tail, or by tossing a Koopa Shell at the tiny Goomba.
Pile Driver Micro-Goombas can be distinguished from their surroundings. Regular Brick Blocks glisten; Pile Driver Micro-Goombas' Brick Blocks do not. Also, the Pile Driver Micro-Goomba's Brick Block is slightly smaller. However, in Super Mario All-Stars's Super Mario Bros. 3 remake, they glistened like any other Brick Block, but were still smaller and even somewhat a lighter color. Super Mario Advance 4 returned the Pile Driver Micro-Goomba's Brick Block to its non-glistening Super Mario Bros. 3 form (though it was, of course, updated Super Mario All-Stars-style along with all of Super Mario Advance 4's other sprites).
Pile Driver Micro-Goombas make one small appearance in The Adventures of Super Mario Bros. 3, in the episode "A Toadally Magical Adventure". Although they have the same characteristics and appearance as Pile Driver Micro-Goombas, they are real Brick Blocks brought to life, and are only referred to "blocks". These blocks were created by Toad's Pipe Monsters after they rebelled against him.
Although they're unrelated, Blockhoppers from New Super Mario Bros. are fairly similar to Pile Driver Micro-Goombas in that they, too, hide in blocks. However, Blockhoppers are not at all related to Goombas (being blue robots of an unknown origin) and can hide in multiple blocks at once, and also have the ability to mimic ? Blocks.
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