Each of them carries a mask that used to be its face when it was human. Sometimes they look at it and cry. (Black)
The entry for Yamask casually introduces a pretty deeply messed up concept as if it was nothing: humans can die and turn into Yamasks. Worse still, it loses all of its human body except the fucking face, WHICH IT CARRIES AROUND AS A MASK. That's some Hannibal Lecter-meets-Nightmare on Elm Street shit.
Although, I guess that answers the "human afterlife" question: they either get turned into soul-fuel for Pokemon or become Pokemon themselves. Pretty ironic punishment for trainers to die and become enslaved Pokemon, constantly haunted by their lost humanity.
What a fun game for kids this is!
Although Gorebyss is the very picture of elegance and beauty while swimming, it is also cruel. When it spots prey, this Pokémon inserts its thin mouth into the prey's body and drains the prey of its body fluids. (Sapphire)
The animal kingdom is filled with messed-up ways for each animal to kill one another. What Gorebyss does, though, is something special: it literally drains you of all your bodily fluids, leaving you a dried-out husk. Worse, it inserts it through your mouth. Luckily, this is just happening to other animals, right? Sorta.
Keep in mind that when you encounter wild Pokemon, they're not attacking your Pokemon initially - they're attacking YOU, and then you throw out your Pokemon to defend yourself. Meaning, if one were to be attacked by a Gorebyss and didn't have any Pokemon on them at the time, you'll become that Gorebyss's personal Blood-and-Bile Slurpee.
It is whispered that any child who mistakes Drifloon for a balloon and holds on to it could wind up missing. (HeartGold)
These Pokémon are called the "Signpost for Wandering Spirits." Children holding them sometimes vanish. (Black2)
Parents need to be extremely careful in the world of Pokemon. Almost any item - from keys, to a sword, to some garbage - could secretly be a Pokemon. Give your child a balloon to hold on to, it might actually be a disguised Pokemon that will kidnap your child and will never be seen again. What a ghost-balloon could possibly want with children is probably a question best left unanswered.
Note: In Pokemon Pearl, the entry for Drifloon is "It tugs on the hands of children to steal them away. However, it gets pulled around instead." So...not always disturbing. A ghost balloon that tries to steal children but gets stolen themselves instead? That's just...sad.
If a traveler is going through a desert in the thick of night, Cacturne will follow in a ragtag group. The Pokémon are biding their time, waiting for the traveler to tire and become incapable of moving. (Sapphire)
This entry thankfully cuts itself short before it reveals exactly what the ROVING GANG OF SENTIENT CACTI plans on doing with the poor souls lost in the desert, but there's an implication that they're not going to give him a ride to the nearest bed 'n breakfast. Really, even if the ROVING GANG OF SENTIENT CACTI were trying to do something nice for you, it would be an unbelievably painful nightmare the second they got near you. Because, quick reminder: they're a ROVING GANG OF SENTIENT CACTI.