Ghost Goomba

Ghost Goombas (generically referred to by Nintendo Power as ghosts ) are Boo-like ghosts of Goombas found in Super Mario Land 2: 6 Golden Coins. They are only present in the third level of the Pumpkin Zone. True to its appearance, the Ghost Goomba is invincible and wavily floats like a Boo, but moves faster and forward like a Goomba. Green Shells and Stars are effective in defeating it. In the Kodansha adaptation, they are specifically depicted as the ghosts of Masked Ghouls.

Perfect Ban Mario Character Daijiten
''' テレクリボー 　ゴースト族 　未練がましい ゲーム　ランド2 ''' クリボーのおばけだ！  あのクリボー（P72）がおばけになったもの. おばけは実体が無いので、マリオの攻撃を全く受け付けない. しかも、動きも銳いので、急いで走り抜けるようにしよう.

 Ghost Goomba  Tribe: Ghost clan Disposition: Regretful Game appearances: Land 2 ' It's the spirit of Goomba! ''The Goomba (p. 72) has become a ghost. The ghost has no physical form and is totally immune to Mario's attacks. Mario must run through it quickly, as it moves in a very unpredictable manner.''

Trivia

 * Ghost Goombas have an unused squished sprite, indicating that they originally could have been stomped.
 * In a KC Deluxe mini-guide, Ghost Goombas are referred to as the ghost of Goombo. In actuality, Ghost Goombas are approximately the size of regular Goombas and even slightly bigger than the game's Boos.
 * A Ghost Goomba appears in the concept art of Super Mario Odyssey, suggesting they may have been planned to appear in the game somewhere early in development.