Perilous Storm
Introduction: I created Perilous Storm in June of 2009. This was during the pre-Giratina-0 period, thats what I call the period before Giratina-0 became popularized. It is essential to the understanding of this team to remember that because Giratina-o was not prevalent, the standard uber stall teams of the period wasn't what it is now. I, and many users I consider to be competent team builders, have made it a practice to focus the team building process on the systematic overwhelming of full stall, as if full stall can be broken it is only a short step to breaking teams that don't have the defensive balance of a full stall team.
Perilous Storm is actually my first "real" ubers team. Like all of my best teams it can be classified as "heavy offense," a bankrupt term (this is a discussion for another time). This team is what really brought me into the ubers metagame, and it is actually somewhat innovative, as I would like to believe that this team set the precedent for special heavy offense in ubers. This team's blueprint put at least 10 different accounts into the top 25 (some into the top 5) in less than a month, and this specific team peaked at 22nd for me, though others went further.
Team Building Process
As I said in the introduction, I build teams to break full stall. At the time when Perilous Storm was created, this is what ubers full stall was according to a Giratina-0 analysis:





The 6th slot usually went to lugia, bulky mewtwo, scarf palkia/dialga, or wobbuffet.
This team is absolutely wrecked by CM giratina-0 (at this time cm giratina-o wasn't immensely common) with proper support that is.Blissey and latias cant really touch giratina-0 and everything else is ohkoed after a cm.

While I new I wanted to use giratina-0, I decided not to pick a specific movset though I knew it would be substitute and calm mind. I wasn't going to count on giratina-0 breaking stall all by itself, it needed support. I needed a pokemon that could be both very threatening to blissey, but also lure in palkia and latias. CM +3 attacks Kyogre was perfect and it would also provide rain. Rain allows giratina-0 to get perfect coverage from dragon pulse and thunder, which were ideal to me, as i didnt want to fight Calm Mind wars with opposing kyogre.


The last member of the "truly" offensive part of this team would be darkrai. As a beginner in ubers I marveled at how threatening darkrai is. On Perilous Storm Darkrai is intended to be a clean-up pokemon, sweeping away the dregs of a depleted stall team.



These 3 pokemon are laughably fragile, they needed something to shore them up against threats like Rayquaza, garchomp, even rock polish groudon. To this end I added bulky mewtwo who handles sweepers with relative ease and has good recovery options.




With 2 slots left, I wanted the very best support pokemon to set up hazards and eliminate the threat of toxic spikes and choice scarfers:






And now there is Perilous Storm in-depth:

Deoxys-e @ Focus Sash
Timid
252 hp/252 speed/4 defense
Taunt
Stealth Rock
Spikes
Shadow Ball
I want the best pure spiker in the game, and I don't settle for imitation sets. Take a close look, no extreme speed, and taunt is included. This is the essential suicide lead, prevent your opponent from getting their stuff up, while you get your own stuff up. Worried about deoxys-a? Half the time they don't even run shadow ball, and ice beam +extreme speed isnt even a KO, so you hit them twice with shadow ball and they're done.
I play deoxys-e very conservatively to be honest. Against opposing deoxys-e and darkrai I just taunt first turn, who is to say that I can't win a speed tie? Pretty much everything else is set-up fodder, I just put down as many layers as possible while i die. The only exception is forretress.I usually just taunt and then switch as I don't want to play around toxic spikes for the rest of the game.

Wobbuffet @ Leftovers
Calm
28hp/ 252special defense/ 228 defense
Safe Guard
Encore
Mirror Coat
Counter
Wobbuffet is the 2nd half of my support engine. It lets Darkrai and Giratina-0 get the turns they need to rip through any team. Wobbuffet is also my only way of handling palkia and dialga defensively. The most important move on this set is the irreplaceable safe guard. My team auto-loses to toxic spikes when wobbuffet isn't around. Wobbuffet is in many ways the glue that holds this team together.
This opening, the classic deoxys-e into wobbuffet, is prevalent on all of the best ubers offensive teams. Many teams go directly into rayquaza to wreck teams now that hazards are down, but instead i go to Giratina-0, who my not be as threatening in general, but on this team it has a greater chance of breaking something so that I can win late in the game.

Giratina-0
Modest
86 hp/ 216 spa/ 96 Spd/ 112 spe
Substitute
Calm Mind
Dragon Pulse
Thunder
Giratina-0 is the main focus off this team, wobbuffet and deoxys-e both help giratina-0 get off the ground. Giratina-0 cant really switch into a strong attack, so make sure you get in a locked in thunder from palkia or something like that. This set is an absolute monster in ubers. The only reliable switch in to this set is specially defensive dialga, who still takes a ton of damage.
It is important to be conservative with this set. You can only afford to use substitute a limited number of times, so you have to make each one count for something, I probably wouldn't waste one finding out if forretress has payback, instead assume that it does and use thunder to hit whatever is switching in. If it is blissey, you can always use substitute then. Be aware to, that Giratina-0 isn't running much speed don't count on outrunning kyogre or groudon.

Mewtwo @ Leftovers
Timid
188 hp/52 special attack/252 speed/16 defense
Recover
Ice Beam
Calm Mind
Aura Sphere
Mewtwo is really a great pokemon, so versatile with its perfect stats and excellent support typing. The idea here is to counter rayquaza, groudon, and darkrai, while getting opportunities to heal when possible. Calm Mind works in a late game coverage sweep. The coverage here is the standard range used in ubers to handle physical attackers. It runs through offensive teams easily with out very much set up. Consider taunt if Baton pass is an issue for you.
One thing you can do with this mewtwo is switch in with 1 layer of toxic spikes down, thereby ensuring you avoid a crippling status such as paralysis. This also prevents you from getting toxiced by blissey meaning you can beat her easily either by pressure stall or Calm Mind. Mewtwo is a pokemon that can run any set which means you often find people playing around moves I don't have just because they are nervous, this is part of what makes mewtwo strong.

Kyogre @leftovers
Timid
252speed/252 special attack/4 hp
Surf
Ice Beam
Thunder
Calm Mind
This is easily the most destructive kyogre set out there. After one calm mind the only uber who can switch in is latias, all others die. This set aims at luring scarf palkia who cannot 2hko with thunder. The Speed ensures that I will tie with other base 90's, and also beat things like defensively invested lugia. This kyogre has enough natural bulk to be considered a check to darkrai and mewtwo. After a Calm Mind bold wobbuffet can be koed (why do you think mine is calm). Latios similarily cannot take on this kyogre as ice beam can sometimes ko after SR. I frequently send in wobbuffet when i do end up seeing latias in order to eliminate it as quickly as possible, as it is easily the biggest threat to my team. This set was relatively unused when I started using it, but I have to say that its probably the most threatening pokemon in the entire game, I can't think of anything with the same raw power.

Darkrai @ Leftovers
Timid
252 speed/252 special attack/ 4 special defense
Dark void
Substitute
Nasty Plot
Dark Pulse
I can't say enough about this set. It is easily the most effective stall breaker i have ever used. The idea is fairly simple, if forretress runs payback it can break giratina-0's substitute, but if it runs payback it can run gyro ball, so darkrai gets in and sets up on it. Notice that I use leftovers to be able to stall Bad Dreams stall effectively. This is far more useful than draco plate which gives an irrelevant boost it power. Substitute is also very useful in catching people sending in things to absorb the Dark Void. I sub and they send in say giratina and i dark pulse it twice for the ko. Now they have to try someother pokemon, and I have gained a huge advantage without even wasting activating sleep clause. This darkrai is a leech seed staller, a set-up sweeper, and move scouter all in one, which gives me the versatility I need when I am using multiple pokemon with similar roles.
Thank you for reading.