When some ghosts die they die wanting something. Maybe money, or rare items, it doesn't really matter what. But whatever it is, they're stuck wanting it, so when they become ghosts it changes them. They're not sad spirits, they're greedy spirits. They have thin necks and bloated stomachs and they want to eat everything, coins, food or humans. And so they will, but eating is extremely painful for them so they also weep.