Illustration by Jim Kay © Bloomsbury

Ghosts are the imprints of witches and wizards who have died and left a part of themselves behind. Only those who are magical can return as ghosts (meaning Muggles can’t become one). However, even though all witches and wizards have the ability to come back as a ghost, those who are smart, don’t.

It is said that those who do return have unfinished business of some sort. There are lots of reasons for this such as regret, fear or guilt. Some ghosts are those with a very strong attachment to the material world who refuse to move on.

Ghosts are transparent, three-dimensional and can pass through solid objects (including people) without causing any damage. Though they do cause disturbances in fire, water and air. If you are in the presence of a ghost the temperature will drop, and if there is more than one ghost around, the temperature drops even further. If you are unlucky enough to have one pass through you, it would feel like someone had emptied a bucket of freezing water over you! They also have the ability to turn flames blue.

While it may seem tempting to remain on earth forever, ghosts are just shadows of their former living selves. They can’t experience much of the world. They can no longer touch anything, eat anything and they won’t be able to learn anything new. A ghost’s level of knowledge and talent remains the same as when they died. Not being able to move on means that ghosts are often not the best company. They will not let go of any grudges or resentments – just ask Nearly Headless Nick about the fact he’s only nearly headless!

As well as not being able to come back as a ghost, Muggles can’t seem to see them. Witches and wizards are much more sensitive to paranormal activity which is why they can see and interact with ghosts. However, that is not to say Muggles are completely oblivious, they might feel that a haunted place is cold or feel creeped out by being there.

Overall, being a ghost sounds like a pretty rubbish deal to us. To be a ghost is to be stuck forever as a shell of yourself – which we can do without.

And how does being a ghost differ to being a portrait, you ask? Let's unpack that next.