What is Hungry Ghost festival?

What exactly are Ghost type Pokemon?

• I'm not sure what a Ghost Pokemon is exactly... In the very first games, there was a deceased Marrowak, who had to be defeated so it could be sent to the afterlife. This implies that not only do Pokemon have souls, but evantually they go to some form of afterlife. Now, Ghost Pokemon can't be the souls of deceased Pokemon, because the soul of the Marrowak appears generically as "Ghost". When the sliph scope is used, it turns into a Marrowak. However, the sliph scope does not turn actual ghost pokemon, such as Gengar, into other pokemon. So Ghost Pokemon can't be the souls of dead Pokemon trapped in between this wolrd and the next, but something different completely. My question is, what? What is a Ghost pokemon?

• Answer:

  Ghost type pokemon are ghosts but not in the sense of being the soul of deceased pokemon or people. The only pokemon who is known to be the ghost of a deceased individual is Yamask and by extension Cofagrigus. It would seem that ghost type pokemon although being spirits were born that way. Meaning they are in some extension alive and therefore can die if not by age but by other means.