Where is your God now?
For me, a Gothitelle was something very scary.
Gothitelle, it even has its own slasher-flick like cry. Also it has shimigami eyes.
I havent seen anyone mention this one so I will, Mismagius!! its so weird looking, not so threatening but i wouldnt like to see it in a dark ally. But who fits the title for threatening/frightning are; Gyarados, Tyranitar, Aggron, Salamence, Gengar, Drapion, Nidoking, Houndoom, Ursaring, Sableye, Dusknoir and Chandelure!
Gyarados is freakishly terrifying; the idea of running into one of those would keep me from ever swimming in any body of water in the Pokemon world. That thing would eat you if it saw you.
I would have agreed that all Ghosts are frightening a couple of years ago but then came Gen V. And I found a pair of Ghost types who won't kill you. One's too cute to be frightening (Golett) and the other has no real interest in harming anyone (Golurk). Now granted, Golurk is a bit intimidating because of his size but the big fella wouldn't actually hurt you. I don't mind those two Ghosties; they're more than welcome on my team.
Now Gengar on the other hand....
Grand Riser, henshin!
Claimed: Golett ~ Iron Fist ~ Shadow Punch ~ Big Pearl ~ Light Clay.
In all honesty, I've always found Houndoom to be the most frightening Pokemon. I have a thing about burns, and (according to the Pokedex) "if you are burned by the flames it shoots from its mouth, the pain will never go away." So, yeah. Supernatural burns that will never end. And probably drive you insane.
we're talking glitchy glitchy goo here!
My YouTube Vids (Pokémon White 2, Randomized Emerald and soon Platinum)
-Why don't use Pokémon who you like instead of powerful ones? You'll have fun in every battle and winning gives more satisfaction!
The fake Groudon. That thing is the most frightening Pokemon ever (if it IS a Pokemon).
Banette. Pokemon version of Chucky.