So, mean flying scorpion looking thing, hmm. Here goes. This is a set I really enjoy. Ev's are geared towards bulk, and surviving even moderate strength neutral stab hits, and even some medium powered stab super effective hits.
Scorpion King (Gliscor) (M) @ Toxic Orb
Ability: Poison Heal
EVs: 252 HP / 44 Atk / 132 Def / 76 SpD / 4 Spe
This ev spread meant to be used on a bulky defensive oriented team, with a core Chansey + Cofagrigus/Dusclops/Dusknoir.
Dual stab, because even in OU, Bug, Grass and Fighting mons are used, and people usually expect Equake + 3 status on Gliscor.
Fling works with Acrobatics, so they either both stay, or both go, and when you move first, negates a big chunk of damage from Knock Off, since you no longer have an item. Knock Off does 65 bp, after Fling, instead of 97.5 bp (50% boost). Last move is kind of flexible and there are reasons for each.
Protect - Guarantees Poisoning the first turn Gliscor is in play, ignores a predictable Knock Off and keeps the Toxic Orb, extra healing with Poison Heal active, scouts moves, 2 turn moves are uncommon, so you don't give them a free turn. If they're playing with a defensive team, protect loses some value.
Roost - Immediate 50% healing, and loss of flying type until end of turn. Easily predictable once your opponent sees it the first time though. They might use the mono ground type to their advantage. If they move first, you don't lose your flying type, so ice hurts.
Toxic - More reliable poison stalling than Fling, as Fling only poisons once, if that.
Fling only fails to poison the foe if they're a Steel or Poison type or one of the 1-2 Pokemon with Immunity ability. Equake usually keeps those mons from switching in, so Fling is usually very safe as long as you don't see Skarmory, Celesteela or Crobat. However, Toxic is usually ran over the secondary stab, which I find to be a bad idea overall.
U-turn (with Protect) scouts moves, gives you momentum, while not being shut down by flying, levitating mons if your only other attacking move is Equake.
You could opt for
If you opt for a super defensive set, instead of tank set at the very top, I'd recommend evs of:
252 HP / 176 Def / 76 SpDef / 4 Spe (Physical Bulk)
252 HP / 132 Def / 120 SpDef / 4 Spe
(Mixed Bulk, I like this set a lot, as most players expect Gliscor to be fairly frail on the special side. At best most Scald/Ice Beam users (with 0 sp atk evs) score a 2hko after Poison Heal. They get outsped by Gliscor, allowing you what is essentially a free turn to Toxic them, before a protect/roost/u-turn/hard switch.