Just caught Regice and it turned out to be really good with a Sp DEF of 308 at Lv 65.
So here's what i want to see:
Regice @ Leftovers/Shell Bell
Clear Body
Not sure what EVs
Careful
-Amnesia
-Ice Beam
-Hammer Arm
-? (probably Curse)
A definite wall. The Careful Nature boosts its already beefy Sp DEF and Amnesia only boosts it further. Ice Beam for STAB and for the effect chance. Hammer Arm for Rock and Steel Types.
Obviously some holes can be poked in this but it isn't completely finished
Also considering a shuffler Garchomp
Regice has a very usable Special Attack at Base 100; why would you use a nature that lowers it, when the obvious choice is going to be to lower its pitiful base 50 attack instead? Drop Hammer Arm, it's attack is too poor to use it. Regice will never be beating Rock/Steel/Fighting types anyway, because they prey on its lower physical defense and force it out. Use Calm if you want more SpD, or Modest if you'd rather run a bulky attacker (since its SpD is already pretty high to boot).
Amnesia is a waste as well; boosting your SpD gives them a free turn to switch in a physical attacker and ignore your Amnesia entirely.
Ice Beam is perhaps the only move you want to keep on Regice. Give it Thunderbolt as well, since it has phenomenal coverage alongside Ice Beam, and one of Regice's advantages over other ice types is that it learns said Thunderbolt. Rest/Sleep Talk also works well on him, since unlike Blissey, he doesn't have nature cure or any other reliable forms of recovery, so he can be easily worn down or crippled by status. Rest will prevent both, while Sleep Talk takes advantage of the would-be hindrance of being put to sleep to recover.
Don't focus on trying to counter Rock/Steel/Fighting; Regice is never going to beat them 1v1. This is why you have teammates.
Gengar @ black sludge
Nature: timid
Ability: levitate
EVs:110hp 230spd 230spatk
Moves: hypnosis
Stealth rock
Nightmare
Dark pulse
Turn.1 hypnosis the opponent can't move If the opponent wakes up redo turn 1 and 2
Turn.2 if hypnosis hits use nightmare
Turn.3-5 use stealth rock
Turn.6 use dark pulse
When the opponent faints use turns 1-2-6
He is also protected from trick unless it is part poison type and even if he does get tricked by a non poison type every turn they will get damaged if it is part poison type than I have a problem
(Footnote: I only use this strategy in competitive battles/hard battles
:>
You do realize that's an illegal moveset, right? Gengar can't learn stealth rock. Not to mention your EV Spread doesn't work, since you can only have 510 total; you put down 570.
Hypnosis only has 60% accuracy. You can't rely too heavily on it, which makes Nightmare gimmicky. If you miss with Hypnosis, Gengar's frailty means it's going to die.
There's no reason to use Dark Pulse on Gengar, when Shadow Ball has almost identical coverage, but Gengar gets STAB on SB.
Black Sludge is also pointless given Gengar is incredibly frail, and likely won't survive more than two attacks total (With it being very likely he'll be 1HKO'ed). Gengar is also not protected from Trick; just because the opponent tricks a Black Sludge onto themselves, doesn't mean it protects Gengar, since the foe can still Trick a Choice Band or Flame Orb or something onto him. Not to mention that Black Sludge doesn't stop them from Tricking again, so they can actually Trick your own Black Sludge onto some other Pokemon of yours.
Using that in a competitive battle will give you problems because it's highly gimmicky.