Well, yeah. They're ghosts. They're supposed to be creepy and lethal. However, nothing is more lethal (based on dex entries, anyway) than Kabutops. They cut you open and drain your body fluids.

And the mushroom on top of Parasect is a parasite, sucking away at the bug's energy and controlling its mind like some sort of zombie-vassal. For a kid's game, some Pokemon are really creepy.

This is exactly why my sprite hasn't left the house for weeks now. It's a dangerous world out there!

"Each of them carries a mask that used to be its face when it was human. Sometimes they look at it and cry."

"These Pokémon arose from the spirits of people interred in graves in past ages. Each retains memories of its former life."

If you thought entries like Shuppet and Banette were morbid, Yamask just went way beyond that.
Poor little guy.

Edit: I'd like to mention that I made this post from a comp in which the image in the OP would not load.

Glad to see my favorite Ghost pokemon isn't that bad & that her pre-evolution is even less threatening to the lives of it's victims...

Didn't know that Gengar's family was that up though, just wow...

Wow, those dex entries never really registered with me. I think there are a few people at Nintendo that might need counsoling.

But yeah there Ghost pokemon, so I guess their entries are gonna be kinda creepy to begin with.

I just noticed that Lampent's marked in green. If it's true that it steals the spirit right when the person's about to die anyway, shouldn't that be marked yellow and not green?

In other news, I'm sure that Ghost types aren't the only Pokemon like this - just that most of the more evil entries belong to Ghost-type Pokemon. It'd be interesting to do a survey of all of them (however time-consuming it may be) to see what other entries are out there.

Like...like Houndoom.
I'm now inspired to look up the dex entries of every Dark-type.

I think Kadabra has something about bringing death if you look at his shadow, or something like that.

It only brings bad luck, not death.

By the way, Shedinja's entry is proven false by this epic webcomic: http://www.rarecandytreatment.com/comics/1246650/the-re-bustening/#cpage

Holy cow, I didn't know Ghost Pokemon could be so creepy! This is definately an interesting topic...

this is another reason why i'm glad that pokedex descriptions are just there for your reading pleasure and have no actual effect on game play. cuz if a youngster defeated ur drifloon and you walked to that same route the next day and see your Drifloon out of ur box or team but standing in that same youngster's place, u kno what happened

I knew there was a reason I didn't like them darned ghost things ...

It is actually a little disturbing ...

Interesting, Pokemon is much more darker then I thought. i kinda like that...

I think Houndoom's entry is kinda scary (its fire brings eternal pain), but I think with ghost Pokemon, it kinda got old with everything stalking you and eating your soul and dragging you to the underworld. But Yamask's is just plain creepy (and slightly sad...)

Interesting... But as far as creepy pokemon, Gorebyss sucks out your body fluids.

I like to imagine a lot of the Pokédex entries are b.s. The entire catch-Pokémon-to-trigger-device-to-show-you-information-it-already-has concept is bogus; I think the player character is writing them in. And makes things up from time to time.

As for why some of the entries are the same in different games? That's just you, getting tired of coming up with new things to say about the same old Zubat and Geodude over and over. And to think you were so ambitious for the Ruby and Sapphire ones.