Champignon blanc translucide au visage de Boo, yeux mi-clos et large sourire

Ghost Mushroom: the spectral power of Galaxy

1322 words | Reading time : 6 minute(s)

ItemBoo MushroomSuper Mario Galaxy

Float, turn invisible, slip through grates — but run from the light. The Boo Mushroom from Super Mario Galaxy turns the plumber into a translucent Boo Mario. This guide breaks down its three powers, its Achilles' heel — the faintest light source dispels it — its direct debt to the Vanish Cap of Mario 64 and its later comebacks.

The Boo Mushroom (Boo Mushroom in English) is one of the most atmospheric power-ups in the whole saga. Pick it up and Mario turns into Boo Mario, a translucent creature able to float through the air and slip through metal grates.

This spectral power, born in Super Mario Galaxy, turns fear into an advantage: where Boos usually terrify the plumber, here they become his perfect disguise for exploring haunted galaxies.

Contents

A power born in Super Mario Galaxy

The Boo Mushroom makes its debut in Super Mario Galaxy, released in 2007 on Wii. The power-up became one of the game's signatures, turning a classic series enemy into a genuine tool for progression.

The power then returns in Super Mario Galaxy 2, released in 2010, then in the port Super Mario Galaxy + Super Mario Galaxy 2 released on Nintendo Switch in 2025. Three console generations for one and the same spectral item.

Its official English name is Boo Mushroom. In his transformed state, Mario becomes Boo Mario and Luigi, Boo Luigi (respectively Boo Mario and Boo Luigi in English). Visually, the hero takes on the look of a white Boo wearing Mario's red cap, his face and moustache staying perfectly recognisable.

Flying, turning invisible, slipping through grates

The transformation opens up a range of moves that are impossible in normal form. It rests on three main abilities:

  • Gliding and floating: tapping the jump button repeatedly lifts Mario gently into the air; holding it down brings him back down smoothly, which is what lets you cross wide chasms.
  • Turning invisible: by performing the Spin (a shake of the Wii Remote), Boo Mario briefly turns transparent and can then slip through metal grates as well as certain walls.
  • Understanding the language of the Boos, Booish, which leads to a few delightful exchanges with the ghosts you meet along the way.

The flip side: in this form, other Boos are drawn to the hero. Touching one ends the disguise and forces you to play carefully through the haunted corridors.

Mario transformed into a translucent ghost passing through a grate in Super Mario Galaxy
Transparent, he floats and slips through grates — but a single ray of light is enough to make him solid again.

Light, its Achilles' heel

The Boo Mushroom is a power as mighty as it is fragile: several situations switch it off instantly, so you have to keep an eye on your surroundings at all times.

  • Light: the moment Boo Mario steps into a beam of light, he is immediately sent back to his normal state. It is the power's most emblematic constraint.
  • Damage: taking a hit costs you the transformation along with the damage suffered.
  • Water: the slightest contact with a body of water dispels the ghostly form.
  • The Launch Stars (Launch Stars): taking one ends the disguise and sends a back-to-normal Mario flying toward the next area.

Worth noting: touching another Boo also cancels the transformation, but without dealing any damage to the player. Light remains the real common thread of this mechanic.

A legacy of the Vanish Cap from Mario 64

The idea of slipping through grates is nothing new: it draws straight from Super Mario 64, released in 1996. That game already introduced the Vanish Cap (Vanish Cap in English), which made Mario translucent for about twenty seconds.

Wearing that cap, Mario could pass through metal fences and certain walls, exactly as Boo Mario would later do with a simple Spin. So the studio revived a cult mechanic by marrying it to the Boo theme.

The lineage is even acknowledged by the dedicated encyclopedias: the bars you can pass through as Boo Mario explicitly recall those of the Vanish Cap. A fine line of continuity between the plumber's first 3D adventure and his galactic epic.

Where to use it: from Ghostly Galaxy to Boo Moon Galaxy

In Super Mario Galaxy, you first discover the power in Ghostly Galaxy (Ghostly Galaxy), where its exact job is to rescue Luigi. Fun detail: since Luigi is scared of ghosts, he runs away if Mario comes near in Boo form, so you have to return to his normal appearance before setting him free.

The Boo Mushroom then shows up again in two other galaxies of the first game: Boo's Boneyard (Boo's Boneyard Galaxy), a chase against a giant Boo, and Sand Spiral (Sand Spiral Galaxy), where flight becomes essential.

In Super Mario Galaxy 2, the item comes back inside Boo Moon (Boo Moon Galaxy), notably during the mission Haunting the Howling Tower (the English name, since no official localised one is documented), which pushes mastery of flight and invisibility to its peak.

The Boo Mushroom at a glance

French name Boo Mushroom
English name Boo Mushroom
Resulting form Boo Mario / Boo Luigi
First appearance Super Mario Galaxy (2007)
Return appearances Galaxy 2 (2010), Switch port (2025)
Powers Flight, invisibility, passing through grates
Weaknesses Light, water, damage, Launch Star
Inspiration Vanish Cap (Super Mario 64, 1996)

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FAQ

  • Which game does the Boo Mushroom appear in?
    It debuts in Super Mario Galaxy in 2007 on Wii, before returning in Super Mario Galaxy 2 (2010) and then in the 2025 Nintendo Switch port.
  • How do you turn invisible as Boo Mario?
    You have to perform the Spin, that is, shake the Wii Remote. Mario then turns transparent for a moment and can pass through grates as well as certain walls.
  • Why is Boo Mario afraid of light?
    Light is his built-in weakness: the moment he steps into a beam of light, the transformation fades and he instantly returns to his normal appearance.
  • Does the Boo Mushroom exist in Super Mario Galaxy 2?
    Yes. It turns up in Boo Moon Galaxy, in particular during the mission Haunting the Howling Tower, which leans on flight and invisibility.
  • Which older power inspired the Boo Mushroom?
    The Vanish Cap from Super Mario 64 (1996), which already let you pass through metal fences and certain walls by making Mario translucent.

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