Im well aware of pokemon lore. My main oc WAS a pokepasta oc. So of course I had to research. Also hypno? You chose the least disturbing example:
Drifloon : It is known as a “Signpost for Wandering Souls,” dragging children to the afterlife.
Phantump: These are stumps possessed by the spirits of children who died in the forest.
Kadabra : It was once a young boy with psychic powers who transformed into a Pokémon.
Nihilego (UB-01 Symbiont. Technically not a pokemon but an ultra beast), which acts as a parasitic organism capable of hijacking human consciousness and physically merging with a host.