Looks like the RNG has some sort of fetish with Poison type Pokémon (First Crobatman, now the Scorpion King) and another decent one.
Ability:
Battle Armor: Opponent’s moves cannot Critical Hit.
An anti-hax ability and pretty useful in defensive minded sets and makes good use of Drapion's nice Defense stat (110) since most of those High Critical Hit moves are Physical. Protects Drapion mainly against Attack Order, Crabhammer, Cross Chop,
DRILL RUN, Shadow Claw, Slash and Stone Edge. It also prevents Frost Breath and Storm Throw's effects (Seriously! Who's going to use these moves?)
Sniper: Power of critical-hit moves is tripled instead of doubled.
Another hax related ability (well, we can make puns around that) and useful when running Cross Poison and Night Slash (Slash is optional), add a Scope Lens to the fray and you can annoy your opponents after taking down Physical walls after a Critical Hit.
Keen Eye: Opponent cannot lower this Pokémon’s accuracy.
Guess what! Another anti-hax abilty, but who's going to use accuracy reducing moves besides Flash? At least Drapion can't have its accuracy lowered after taking a Mud-Slap or a Mud Bomb.
Pros:
Unlike every single Poison-type Pokémon (except Stunky and Skuntank), Psychic type moves won't touch Drapion (unless you are facing a Pokémon with Miracle Eye)
Four resistances to Grass, Poison, Ghost and Dark.
Only one weakness to Ground (unfortunately it's a common type considering the massive amount of Pokémon able to use Earthquake or Earth Power)
Decent Attack (90) and Speed (95) and nice Defense (115)
Immune to Toxic Spikes
Cons:
Doesn't take special moves very well (75)
Weak to a VERY common type, though it's Drapion's only weakness
The Scorpion King
Drapion@Scope Lens
Ability: Sniper
Nature: Adamant/Jolly
EVs: 252 Atk/4 Def/252 Spd
Cross Poison
Night Slash
Aqua Tail
Earthquake/Fire Fang/Ice Fang/Slash
Say hello to Critical Happy Drapion (Someone said that to my Scope Lens Gallade in Platinum)!
Cross Poison and Night Slash are your obvious STAB moves of choice, with the Critical Hit ratio boost provided by Scope Lens, while Aqua Tail covers Drapion's only weakness to Ground type moves.
The last move slot depends of what you want to cover.
Earthquake, DAT type, DAT power, DAT coverage.
Fire Fang, if you really hate those pesky Bug/Steel types.
Ice Fang, though redundant against most Ground types where Aqua Tail hits anyway, it has a chance against Dragons.
Slash gets a mention because of its high Critical Hit ratio.
Anyway, your opponent won't like taking a Sniper Critical Hit, even if it's from a not very effective move.
Prediction for next week:
(I want to see the freaking three headed dragon of EVIL someday)
