Separate names with a comma.
Iron Barbs / Rough Skin
Has anyone considered abilities like Static or Cursed Body? It's true they also work if our CAP survives the hit, but it does make the opponent wary...
No Flavor Ability
Volkraken is a spineless Pokémon, so Limber might work. With a decent speed, this might be rather useful, so I'd pick Illuminate as a second choice.
Allow Sludge Bomb
Allow Sludge Wave
No Competitive Ability
Battleship + Chirp
However, being able to easily paralyze Mega Kanga could turn out useful - if it weren't for the fact that unboosted Earthquake will nearly OHKO...
Giratina-O might be smart because you don't have any defense against Ground otherwise... also, you can't really do much to Ho-oh, other than trying...
When will we have the first usage statistics for OU to determine the UU tier?
That feature exists already in the form of level-up moves...