Here is another creation made by Farawaysoul and I. Like the PressureStall Mewtwo set I posted, this requires residual damage such as Toxic Spikes/Spikes/Stealth Rock to work to the maximum of its potential.
The Indestructible Wall (Barring crits)
--------------------
--------------------
Deoxys-D @Leftovers
Nature: Calm
Ability: Pressure
EVs: 252 HP 160 Def 56 SpD 40 Spe
-Taunt
-Recover
-Agility
-Cosmic Power
--------------------
The first thing you might say is, "What!?" and burst out laughing. "It doesn't even have any attacking moves! If it's Taunted, that's the end of it!" However, I have a very good reason for it, and I'll tell it to you upfront; Agility and Taunt. Agility will boost the speed of this pokemon to a sky-high rate of 506, or just enough to outrun a +speed Deoxys-e! In other words, once you Agility, not even Aerodactyl can come in and Taunt you. Now, Deoxys Defense is the Taunter.
With Taunt, Deoxys Defense Form is near invincible against other Taunters and status users that threatened it before. Deo-D can even Taunt RestTalkers which hinder the Toxic stalling from the Spikes, and instead will force them to go without recovery. Even Blissey cannot Aromatherapy and heal status. As you can see, Taunt depends heavily on Agility. However, once you pull off an Agility, the fun begins.
You should now proceed to either Taunting the foe if you are afraid of Taunt or a boosting move such as DD that can ruin your next step. If you suspect the foe has no moves like these that can cause you harm, proceed to the next step: Cosmic Power. This is a move that will add +1 to both your defenses, making Deo-D an almost impenetrable wall except by critical hits. With the given EVs, a Life Orbed +Atk Scizor will deal 52% maximum to Deo-D with U-Turn (even less with X-Scissor), just outside the kill range of Leftovers. Another advantage given by Agility, I forgot to mention, is that you will get to Recover before the opponent's attack, meaning your stalling capabilities will skyrocket now that you outspeed the attacker.
Example
Deo-D used Cosmic Power!
Deo-D's defense rose!
Deo-D's special defense rose!
Darmanitan used U-Turn!
Deo-D lost 32% of it's health!
Scizor switched into Deoxys Attack Form!
Scizor was hurt by the Life Orb.
Deo-D used Recover!
Deo-D regained 50% of it's health.
Gengar used Shadow Ball!
Deo-D lost 45% of it's health! (Max damage again)
Deoxys Attack Form was hurt by the Life Orb.
Deo-D used Recover!
Deo-D regained 50% of it's health...
This continues until the attacker gets a critical hit or the PP is Pressured out completely. Toxic damage will also kill them off. In this case, Shadow Ball could possibly lower the defense if used repeatedly. For this reason, it is wise to use Cosmic Power as often as possible. As you can see, though, you slowly regain health throughout the game by Leftovers added to the total health Recovered minus the damage done. When you feel you have enough health left to take a hit and be fine, use Cosmic Power again, and repeat the process. If something pops up that could hurt you, immediately do something about it, but don't get too hotheaded. Just let information come into your brain, analyze what you see on the screen, and you can deal with it. Deal with it quickly, but accurately. Take time to think over your next move, but don't drag it out over two unless you see a way to get out of it. When you have a chance, immediately Cosmic Power unless you see something that would kill you off in the next hit, or a Status/Taunt user. Chances are, you will pull it off and become invincible and indestructible except by Critical Hits.
Critical Hits
Once you get about two Cosmic Powers, you absolutely cannot be taken out by ordinary means of offense other than Chance. Critical hits will be devastating to the user, but only if they are:
A) Boosted by STAB or Choice Items, and very powerful
Example: Dragonite Life Orb Outrage
B) Boosted by STAB or Choice items, and Super Effective
Example: Scizor's Life Orb Bug Bite
C) Coming off of monstrous special attack and Super Effective
Example: Gengar's Shadow Ball
In these cases especially, Deoxys-D will faint. However, this would be devastating to any ordinary staller also, so I suppose there is nothing that is terrible about these situations, nor unique to this set. It all depends on chance here: That is the primary enemy.
Ways to take this set down
A) Attack before it sets up enough to threaten it out or 2HKO it. Attack with a incredibly powerful move boosted by STAB before it sets up
Example: Politoed Hydro Pump
B) Attack with a remotely powerful move boosted by STAB that it super effective before it sets up
Example: Tyranitar's Crunch
C) Attack with a remotely powerful move that is super effective coming off of monstrous attack/special attack before it sets up
Example: Gengar's Shadow Ball
D) Attack with a high critical hit ratio move after it sets up and pray
Example: Scizor's Bug Bite
E) Bewilder it with repeated hits from U-Turn after it sets up and switch into a pokemon with high attack power that can finish off the weakened Deo-D and posesses Taunt, thus threatening it with either a KO or a Taunt
Example: Scizor's U-Turn coupled with Tyranitar's Taunt/Crunch
F) Keep attacking in hopes of getting a Critical hit after it sets up. This is very rare, and not recommended unless it is a last resort. In addition, you will also need a move from the above section labeled "Critical Hits"
Example: Any move from the above list
EV's
There are several different ways to EV Deoxys-D, but I have listed the most obvious. Speed is there to outrun +Spe Ninjask, while the Special Defense is designed for a Modest, Life Orbed Gengar Shadow Ball dealing less than 50% in one blow. Max HP is for obvious reasons.
Countering Swampert
Swampert cannot hope to break through this Deoxys. Taunt prevents it from Cursing, and Waterfall does pitiful damage. With Toxic Spikes support, Swampert will be blown to pieces. Even without Toxic Spikes, Deoxys comfortably outstalls Swampert's Waterfalls and prevents it from doing anything else thanks to Taunt. Swamp expert? More like Swamp Noob.
I'm not sure why this Swampert feels the need to run Mental Herb, but change Leftovers to Lum Berry and you will win anyway.
This is all on Deo-D's PressureStall+Toxistall set. If you want more information, or something is unclear, or you have found a flaw in it, please comment here and I will review it and change it. Thank you for your support!