Intangibility

Intangibility is a magical state or property that allows a person, creature, or object to pass through solid matter. This phenomenon defies the normal laws of physics, enabling movement through physical barriers without causing damage to either the intangible entity or the solid object. It is most prominently observed in supernatural beings, such as ghosts, but is also a feature of certain magically constructed enchantments, like the entrance to Platform Nine and Three-Quarters.

The primary effect of intangibility is the ability to phase through solid objects. However, this state is not a form of invisibility; intangible beings like ghosts remain visible, typically appearing as pearly-white and translucent figures. When an intangible being passes through a living person, it induces a distinct and unpleasant physical sensation. This is described by Harry Potter and others as a sudden, intense cold shock, akin to being plunged into ice-cold water. Nearly Headless Nick confirms this effect is a known consequence of his spectral state. While mostly unable to interact with the physical world, some intangible entities retain a limited capacity to affect their environment. For instance, Moaning Myrtle is capable of splashing water in her bathroom, and ghosts can cause a noticeable drop in temperature in their immediate vicinity. This is distinct from the abilities of a poltergeist like Peeves, who can fully manipulate physical objects.

Intangibility manifests in the wizarding world in several key ways:

• Spectral Beings: The most common form of intangibility is an inherent property of ghosts, who are the imprints of deceased witches and wizards. As spirits, they are permanently non-corporeal and can drift effortlessly through walls, ceilings, and furniture. Notable examples at Hogwarts include Nearly Headless Nick, the Bloody Baron, the Grey Lady, the Fat Friar, and Professor Binns.
• Magical Architecture: The principle of intangibility is applied to enchantments on physical locations. The most famous example is the barrier between Platform Nine and Platform Ten at King's Cross Station in London. This solid brick wall serves as a magical gateway to Platform Nine and Three-Quarters, and witches and wizards can pass directly through it to board the Hogwarts Express. The magic appears to grant temporary, localized intangibility to the user in relation to the barrier itself.

Despite their non-physical nature, intangible beings are not entirely immune to the effects of powerful magic.

• Magical Harm: Nearly Headless Nick was Petrified by the gaze of Salazar Slytherin's Basilisk. While he did not die again, he was rendered immobile and smoke-coloured until cured by Mandrake Restorative Draught, proving that potent Dark Magic can affect a ghost.
• Physical Interaction: Ghosts cannot consume physical food or drink, as it will simply pass through them. This is a source of great frustration for them, as seen during Nearly Headless Nick's Deathday Party, where the food was rotted to appeal to their senses of smell and sight.

• Poltergeists: A poltergeist, such as Peeves, is often mistaken for a ghost but is fundamentally different. Described as an “indestructible spirit of chaos,” a poltergeist is not an imprint of a deceased soul and, crucially, can interact with the physical world with great force. Peeves constantly throws objects, unscrews chandeliers, and causes physical mayhem, abilities far beyond that of a typical intangible ghost.
• Dementors: Dementors are amortal, non-being creatures that possess an ethereal, phantom-like quality, gliding without touching the ground. However, they are not truly intangible, as they can physically seize a victim to perform the Dementor's Kiss.
• The Veil: Located in the Death Chamber within the Department of Mysteries, the Veil is an ancient, shrouded archway through which one can pass. This is not a form of intangibility but rather a one-way portal between the worlds of the living and the dead.

• In the film adaptations of the *Harry Potter* series, the act of passing through the barrier to Platform Nine and Three-Quarters is shown with a distinct visual ripple effect as a person merges with the solid brick wall (film).
• The visual effects for ghosts in the films depict them as shimmering, semi-transparent, and glowing blue-white figures, faithfully adapting their description from the novels (film).