Ghosts generally have a pale, white complexion, and a translucent appearance, though the level of translucency can vary. Ghosts can vary in appearances, ranging from looking very humanoid to being nothing more than floating heads with arms and tails. One of the best-defined physical characteristics of Ghosts is their lack of legs, which is present in all members of their species, including the Mimic Ghost (even after it transformed into Sonic/Tails) and the pumpkin ghosts despite how vastly different its anatomy is.
Characteristics and culture
While the nature of Ghosts is unclear, Sonic the Hedgehog (2006) seems to imply that Ghosts are the sprits of those who have passed away, though given how vastly different Renzo and Antonio are in comparison to other Ghosts in the series, this may not be the case. It may also be that the term “Ghost” refers to two separate creatures, with one referring to spiritual creatures such as King Boom Boo while the other refers to the spirits of dead creatures such as Antonio.
Most Ghosts seem to have a mischievous and downright childish personality, as they appear to enjoy playing pranks on others. This is exemplified by Lah, who spends most of her time laughing at the pictures of scared children. Also, Boos often scare intruders after popping out of the ground and hold onto them for sometime before letting go and vanishing. Pumpkin ghosts are another example of the Ghosts’ prankster behavior, as they will suddenly appear, simply stand in place and laugh before disappearing. However, with that said, there are certain Boos and pumpkin ghosts that will try to harm others, which may hint at more malicious mannerisms. King Boom Boo is another example of more malicious Ghosts, as he is shown laughing at the pain of others.
Powers and abilities
Ghosts share a handful of similar powers, which include levitation, turning invisible, and intangibility, though some members possess powers unique to themselves: King Boom Boo can breathe and create blue flames, while Su and Wu can fuse with one another.
As shown by King Boom Boo and the Hyudoros, Ghosts are generally weak to light, which is why they reside in dark, indoor areas (such as Aquatic Mine and the pyramid of Sandopolis) and only come out at night and sunset when there is little to no light.
Ghosts have the ability to merge with walls and floors, as demonstrated by King Boom Boo, Su and Wu. Some Ghosts, such as Lah and the Mimic Ghost, have also shown the ability to shapeshift at will, taking on the forms of other beings.
In other media
In the anime series Sonic X and its comic book spin-off published by Archie Comics, Booms, Boom Boos, and King Boom Boo are natural inhabitants of Earth rather than Sonic’s world. They dwell within a pocket dimension within an abandoned castle and are released from their sleep when the Talisman is removed. Another Ghost, known as Captain MacGuffin, is the spirit of a deceased pirate.
In the Sonic the Hedgehog comic series and its spin-offs published by Archie Comics, Ghosts exist on Sonic's World. Knuckles has explained that Ghosts are either vapor or solid. If they want to touch anything, they have to turn tangible, which is when they are vulnerable to harm.
Sonic the Comic
In the Sonic the Comic series, there are Hyudoros whose characteristics and abilities parallel their game counterpart. Two other Ghosts who were formerly living beings also appear in this series, namely Filch and the Spirit of the Herd.