A »hungry ghost«; the preta of India. Invisible to human eyes, a gaki is the spirit of a greedy or gluttonous human being punished in the afterlife. Sometimes a gaki will become visible, and it will then look like a hideously starved human, with an equally awful swollen belly, and its mouth and throat shrunken: for this is the punishment of the gaki, that they hunger and thirst, but cannot easily eat or drink. The gaki is further tormented by being able to eat only one sort of thing, and this thing repellent; often, the food will be the human dead. Sometimes, however, the victual ordained is dangerous to the living, being something in the line of fresh human blood. Then the ghost will be a great threat and must be exorcised. Either way, the gaki knows that its diet is despicable and suffers further thereby.

Hearn tells us of a second type of gaki: those spirits who have nobody to make for them the offerings of food and tea. To sate their hunger and thirst, these gaki will enter the bodies of the living, sharing in their nourishment. This is the cause of fever: for when the gaki first passes into its host, that person will feel the chill of the lifeless spirit, but, as the gaki becomes warm, this warmth naturally exudes into the body of its host which surrounds it, and the host becomes very hot. Eventually, the gaki will go away, and the fever abate: yet this is a temporary respite, claims Hearn, as the gaki will return »at exactly the same hour upon another day« to take its nourishment again. As with most ailments, and indeed the other type of gaki, a Buddhist priest is best suited to cure such an affliction.